Effects Of Dietary Intervention Research Articles

201 The effects of the supplementation of a Zinc-amino acid complex in pig nursery diets with differing pharmacological levels of zinc oxide and complexity

Abstract Diet complexity (DC), which has significance in nursery pig production, generally refers to a greater number of highly digestible ingredients. Increased DC may have even greater significance in scenarios of reduction or withdrawal of zinc oxide (ZnO) in nursery diets. The objectives were to determine 1) the impact of adding Zn-amino acid complex (Zinpro ProPath Zn) to mid- (MC) and low-complexity (LC) diets on nursery pig performance and health compared with a high complexity (HC) diet, and 2) the impact of Zinpro ProPath Zn in diets with and without pharmacologic levels of ZnO. A total of 2,400 mixed-sex weanling pigs [initial body (BW) weight = 5.79 ± 0.15 kg] were assigned to 1 of 5 dietary treatments during nursery (42 d) as follows: 1) HC; MC diet with 2) MC+ZnO) or without 3) MC-ZnO) pharmacologic ZnO; and LC diet with 4) LC+ZnO) or without 5) LC-ZnO) pharmacologic ZnO. All diets except HC were supplemented with Zinpro ProPath Zn (125 mg/kg Zn) and ZnO [3,000, 2,000, and 0 mg/kg Zn during Phases I (14 d), II (14 d) and III (14 d), respectively]. Different DC were achieved by manipulating the inclusion of spray-dried plasma, soy protein concentrate, and whey protein. Growth performance, onset of feed intake, fecal dry matter, number of injectable treatments administered, and serum acute-phase response were assessed. Pigs fed HC (20.0 kg) had greater final BW (FBW) compared with pigs fed MC-ZnO (18.8 kg), which had greater FBW compared with pigs fed LC-ZnO (17.5 kg; SEM = 0.34; P < 0.05). Average daily feed intake (ADFI) was greater in pigs fed HC (0.46 kg/d) compared with MC-ZnO (0.43 kg/d) and LC+ZnO (0.42 kg/d), which had greater ADFI compared with LC-ZnO (0.39 kg/d; SEM = 0.01; P < 0.05). Similarly, average daily gain (ADG) and gain to feed ratio (G:F) were greater in pigs fed HC (0.33 kg/d, 0.72 kg/kg, respectively) compared with pigs fed LC (0.27 kg/d, 0.67 kg/kg, respectively), regardless of ZnO (SEM = 0.01; P < 0.05). There was no effect of dietary treatments on the fecal dry matter or on the onset of feed intake of pigs (P > 0.10). The number of injectable treatments administered was greatest in LC-ZnO (62.7%), followed by LC+ZnO (50.6%), MC regardless of ZnO (44.0%), and HC (36.7%; SEM = 1.04; P < 0.05). Serum alkaline phosphatase was less in LC-ZnO than the other groups (229.8 vs. 280.9 ± 11.9 IU/L; P < 0.05). Taken together, feeding HC diets during the nursery appears to be effective in improving performance and health of pigs, particularly when compared with MC and LC diets without ZnO. Moreover, the addition of Zinpro ProPath Zn may partially attenuate the negative effects of ZnO removal in MC, but not LC, diets.

PSVI-8 Effect of botanical extracts and calcium gluconate fed during lactation on sow and litter performance

Abstract The objective of this study was to investigate the effect of two levels of botanical extracts and botanical extracts in combination with calcium gluconate on sow and pig performance. A total of 541 sows (average parity 2.6, range 0-8) were used in 9 weekly farrow groups. Sows were housed in individual farrow stalls 5 d before the expected farrow date where treatments diets were fed until weaning at 21 d post farrowing. Sows were fed a fortified corn, soybean meal, and corn DDGS diet meeting or exceeding NRC 2012 nutrient requirements for lactating sows. The two test ingredients were 1) botanical extracts contained a proprietary formulation of turmeric, capsicum, and black pepper oleoresins (Fytera Care, Selko USA, Indianapolis, IN), and 2) calcium gluconate replaced corn in the diet. A general gestation diet void of test ingredients was fed before housing and after weaning. Dietary treatments were: 1) basal lactation diet (CON), 2) 150 ppm botanical extracts (150TCB), 3) 200 ppm botanical extracts (200TCB), and 4) 150 botanical extracts and 1000 ppm calcium gluconate (150TCB+CaG). During lactation, sows were allowed ad libitum access to water and feed. Pigs had unlimited access to sow and water. Pigs were cross-fostered within dietary treatments within 24 h of birth to meet a minimum of 75% and maximum of 2 pigs in excess of functional teats of the sow. Excess pigs were fostered to non-treatment nurse sows. Pig mortalities were recorded daily. Weaned sows were observed for 14 d for estrus detection. Statistical analyses included a two-way ANOVA with fixed effect of dietary treatment, random effect of farrow room, and parity as a covariate. Treatment contrasts were analyzed by Student’s t-test. Sow performance measures did not significantly differ between treatments (Table). Pig mortality was significantly (P < 0.001) reduced for both 150TCB and 200TCB compared with CON and 150TCB+CaG treatments. Other pig performance measures were not significantly affected. However, treatment contrasts showed a greater (P < 0.05) pig weaning weight for 200TCB compared with the CON. Analyzing data by parity class of 0, 1-5, 6-8 showed that piglet mortality was affected significantly (P < 0.02) in parities 1-5 and 6-8 but not in parity 0. Pig weaning weight tended (P < 0.06) to be affected in parity 0, but not in higher parity sows. Treatment contrasts showed a greater weaning weight for pigs on the 150AFP and 150TCB+CaG treatments versus CON. In conclusion, feeding botanical extracts at 150 and 200 ppm decreased pig mortality and the addition of calcium gluconate negated the improvement in mortality.

276 Effects of a phytogenic feed additive fed during lactation on sow and litter performance

Abstract The purpose of this study was to investigate the impact of a phytogenic feed additive on sow and litter performance. Six cohort groups of sows (n = 250) were used in this experiment. Dietary treatments were: 1) a corn-soybean meal diet (Control); 2) Control containing 150 ppm of a phytogenic feed additive (Low); and 3) Control + 200 ppm of a phytogenic feed additive (High). The feed additive contained a proprietary formulation of turmeric, capsicum, and black pepper oleoresins (Fytera Care, Selko USA, Indianapolis, IN). Sows were moved to a farrowing room and housed in individual farrowing stalls at 109 d of gestation. Diets were formulated to meet or exceed nutrient requirements for lactating sows, as outlined by NRC (2012). During lactation, sows were allowed ad libitum access to feed and water. Piglets were cross-fostered within dietary treatments within 24 h of birth to equalize suckling intensity as much as possible. Piglet mortalities were recorded daily. Statistical analyses included a one-way ANOVA with repeated measurements in time when appropriate. The statistical model included the fixed effect of dietary treatment, and the random effect of cohort group with parity as a covariate. We observed no significant interactions between dietary treatment and time for any measured response variable. Average daily feed intake of sows, sow body weight, wean-to-estrus interval, and the proportion of sows expressing estrus by d 14 postweaning were not significantly different across treatments (Table). We observed a tendency (P = 0.074) for increased loss of backfat depth during lactation for sows fed Low and High compared with sows fed Control diet. Dietary treatments did not affect litter size, litter weight, or litter weight gain. Percentage of piglet mortality before cross-fostering tended to be less (P = 0.056) for High-fed sows compared with Control sows. However, piglet mortality after cross-fostering was not affected by diet. In conclusion, under the conditions of this experiment, feeding 150 or 200 ppm of the phytogenic feed additive to lactating sows did not substantially improve sow or litter performance.

247 Evaluating the use of soybean hulls on growth performance, carcass composition, and digestibility when fed to grow-finish pigs

Abstract The addition of fiber to grow-finish diets is commonly utilized in swine production formulation as energy costs increase. The objective of this study was to determine the effects of feeding soybean hulls (SBH) at increasing levels to grow-finish pigs on growth performance, carcass characteristics, and apparent total tract digestibility (ATTD) of nutrients. Utilizing 192 grower pigs [PIC 337×1050, initial body weight (BW) = 21.99 ± 2.75 kg] that were randomly assigned to split sexed pens (n = 12 pens/treatment), pens were assigned to one of four dietary treatments and fed over three feeding phases for the estimated BW ranges of 22 to 50 kg, 50 to 86 kg, and 86 to 127 kg. Diets were formulated to represent conventional corn and soybean meal diets, containing increasing levels of SBH at: 1) 0% SBH (0%); 2) 7.5% SBH (7.5%); 3) 15% SBH (15%); and 4) 22.5% SBH (22.5%). Within phase, diets had equal SID Lys:ME and energy was allowed to float. Individual BW and pen feed disappearance were collected for each phase to calculate pen average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency gain to feed ratio (G:F). On d 56 of study and during phase 2, 32 gilts (n = 8) were placed into individual metabolism crates, where total urine and feces were collected for 72 h to measure ATTD of gross energy (GE), nitrogen (N), neutral detergent fiber (NDF), and acid detergent fiber (ADF), then returned to original pens. At the completion of study, carcass weight, backfat depth, and loin depth were collected. Data were analyzed with the fixed effects of dietary treatment by ANOVA, linear, and quadratic contrasts. Pen served as the experimental unit for performance and carcass characteristics and pig as the experimental unit for ATTD analyses. Overall, as SBH increased from 0% to 22.5%, ADG tended to decrease (linear P = 0.060) with no difference in ADFI (P > 0.05), resulting in an overall decrease in G:F (0.38, 0.37, 0.36, 0.35; linear P < 0.001; 0, 7.5, 15 and 22.5% SBH, respectively). Final BW tended to decrease (linear P = 0.069) and carcass weight decreased (102.9, 102.7, 99.7, and 96.5 kg, linear P < 0.001) as SBH increased in diet. Carcass fat depth (P = 0.014) and loin depth (P = 0.006) linearly decreased with increasing levels of SBH in the diet. Increasing levels of SBH from 0% to 22.5% decreased ATTD of GE and N (linear P < 0.001) and tended to increase ATTD NDF and ADF (linear P = 0.056 and P = 0.073, respectively). Altogether, these data suggest increasing dietary SBH in grow-finish pig diets decreases growth efficiency and the digestibility of GE and N. Further, feeding high inclusion rates of SBH negatively impacts carcass yield, backfat and loin depth.

258 Nutritional strategies allowing inorganic phosphates reduction in maintaining maximum growth performance and bone mineralization in piglets

Abstract Phosphorus (P) is an essential component for optimal maintenance of growth and bone mineralization but its inclusion in animal feed is a core concern for economic and environmental concerns in ensuring sustainability of this resource. This study aimed to test impacts of different nutritional strategies such as dietary calcium (Ca) reduction and phytase superdosing for piglets fed without inorganic phosphate. A total of 147 piglets Piétrain*(Large White*Landrace) were divided among 5 experimental diets. Three levels of digestible P were tested (0.21%, 0.27%, 0.33%) by adding monocalcium phosphate (MCP) from 1) a negative control diet (NC) without MCP, 2) a diet with 0.3 % MCP (NC+0.3 % MCP), or 3) a diet with 0.6 % MCP (NC+0.6 % MCP). Those three diets contained 250 FTU/kg of phytase and a minimum amount of phytate set at 0.27%. All dietary treatments were formulated following a constant Ca:digestible P ratio at 2.1. The other two diets were formulated with two phytase’ doses added on top of the NC diet 4) 2,000 FTU/kg (NC+2000 phy) or 5) 3,000 FTU/kg (NC+3000 phy). Piglets were weighed individually at 42, 55 and 69 d of age, and feed intake per phase was recorded per pen. Average daily gain (ADG), daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated. At the end of the experiment, right metacarpal was removed from 12 animals per treatment to analyze bone mineralization. Data were submitted to an ANOVA including effects of dietary treatments and body weight at start of the trial using JMP 16.2.0. Differences among means were separated by a Student’s test and significance accepted at P < 0.05. Liveability % was not different between treatments. The reduction of Ca and digestible P in NC did not affect growth performance (P > 0.05) but reduced bone ash % compared with PC (P < 0.05, 30.4 % vs 34.6 %, respectively). Phytase supplementation at 2,000 and 3,000 FTU/kg improved body weight gain (28.8 kg for animals fed NC vs 30.0 kg for NC+2000 phy vs 30.2k g for NC+3000 phy, P < 0.05), feed efficiency (1.60 vs 1.50 for NC and NC + 3000 phy, respectively; P < 0.05) and bone mineralization (P < 0.05). This experiment confirms the benefit of reducing the Ca and concomitantly P levels in piglet feed without impairing growth performance by optimal use of phytase that also provides the ability to overcome dependence on inorganic phosphates.

17 Effect of branched-chain amino acids on lactating sow and piglet performance

Abstract Sows (n = 360 PIC 1050 and Genesus) were used to investigate the effect of various branched-chain amino acid (BCAA) levels on sow lactation and litter growth performance. Upon entering the farrowing room, sows were blocked by parity group (P0, P2, P3+) and randomly assigned to one of six dietary treatments containing various levels of BCAA. Experimental diets were formulated to various standardized ileal digestible (SID) leucine, isoleucine, and valine levels by replacing cornstarch with L-leucine, L-isoleucine, and L-valine. Levels of the BCAA were expressed as ratios to SID lysine and were formulated at 114 or 180 for Leu, 56 or 64 for Ile, and 64 or 120 for Val. Diets were formulated to be isocaloric (3.23 Mcal ME/kg) and met or exceeded all other NRC (2012) essential amino acid and vitamin and mineral recommendations. Sow body weight (BW), backfat, and body condition score were recorded at the time of entry into the farrowing room and at the time of weaning. Piglet litter weights were recorded after cross-fostering and at weaning to determine litter growth rate. Data were analyzed using generalized linear mixed models with fixed effects of dietary treatment and parity group and a random effect of lactation group. The models were fit using R version 4.3.1 (R Core Team, 2023). The sow and her litter were the experimental unit, and results were considered significant if P ≤ 0.05 and a tendency if 0.05 < P ≤ 0.10. Sows nursed piglets for 21.3 d (P = 0.998). The mean parity by treatment ranged from 3.8 to 3.9 (P = 0.999). After farrowing, the mean estimated sow BW was 219 kg, with a range between treatments of 216 to 221 kg (P = 0.651). On average, sows gained 2.82% of their BW (P = 0.696) with an average daily feed intake (ADFI) of 8.75 kg/d (P = 0.932). However, as expected, sow Leu, Ile, Val, and total BCAA intakes were different across treatments (P ≤ 0.001). Sows entered the farrowing house with an average of 11.50 mm of backfat (P = 0.919) and lost 6.04% backfat through lactation (P = 0.667). Sows started the trial with an average of 14.1 piglets/sow (P = 0.967) and weaned 12.6 piglets per sow (P = 0.981) with a piglet average daily gain of 0.22 kg/d (P = 0.193) and a daily litter growth rate of 2.89 kg/d (P = 0.291). In conclusion, there was no evidence of an effect of the various leucine, isoleucine, and valine levels evaluated in this study on lactating sow and piglet performance.

260 Effect of different doses of phytase (HiPhorius) and two primary calcium sources on nutrient digestibility, retention and blood parameters in weaned piglets

Abstract An 18-d study evaluated the effect of increasing phytase levels in diets with limestone or Ca-formate on Ca and P digestibility, P retention, and blood inositol, Ca, and P in weaned piglets. At weaning, male piglets [n = 60; 29.8 ± 1.10 d of age; initial body weight (BW) = 8.8 ± 0.31 kg) were randomly allocated to ten diets formulated as a 2 × 5 factorial design with 2 primary Ca sources (limestone or Ca-formate) and 5 Ca/P levels. There was a positive control diet (PC; 0.76% Ca, 0.34 dP) and 4 negative control diets (NC; 0.56% Ca, 0.34% dP) supplemented with phytase at 0, 750, 1,500, and 3,000 FYT/kg. At d 10, piglets were individually housed in metabolism crates and fed 3.2 x metabolic weight. On d 14 to 18, fecal and total urine samples were collected. Apparent total tract digestibility (ATTD) was calculated for dry matter (DM), organic matter (OM), crude protein (CP), ash, Ca, and P using TiO2 as marker. Urinary P was measured to calculate P retention. These data were analyzed as a 2-way interaction. On d 0 (baseline), 8 and 18, blood samples were collected to analyze serum Ca and P, and plasma inositol. Blood data were analyzed as a 3-way interaction. Results indicated that piglets fed Ca-formate had greater ATTD of Ca (75.0% vs. 71.4%, P < 0.01) but decreased ATTD of P (66.4% vs. 68.8%, P < 0.01), than piglets fed limestone. Phytase supplementation improved ATTD of DM, ash, OM, CP, P, and Ca compared with the NC and PC. An interaction between Ca/P levels and Ca-sources was observed for urinary P (P = 0.03), as there were no differences between Ca sources in piglets fed the NC or the 750 FYT diets, but piglets fed the PC diet and the NC+1,500 or 3,000 FYT with limestone had greater urinary P compared with Ca-formate. A 2-way interaction between Ca/P levels and d was observed for plasma inositol (P = 0.012). On d 8 and 18, there was no difference between the NC and PC;, however, phytase supplementation at 750, 1,500, and 3,000 FYT increased plasma inositol on d 8 (58.2, 80.7, and 89.5 μmol) and d 18 (70.2, 85.4, and 106.4 μmol). There was only a main effect of Ca/P levels in serum P. Compared with the NC (73.7 mg/L), the PC and the NC+750, 1,500, and 3,000 FTU/kg increased serum P (90.3, 89.1, 87.6, and 93.2 mg/L, respectively, P < 0.01). There was no effect of Ca source on blood inositol and P. No significant dietary treatment effects were observed in serum Ca. In conclusion, using Ca-formate instead of limestone increases Ca digestibility but reduces P digestibility, likely due to a greater Ca solubility of Ca-formate. This suggests that diets should be formulated based on digestible Ca instead of total Ca.

Effects of zinc supplementation and implant abscess on the immune system and growth performance of growing beef steers.

Seventy-two Angus-cross steers (261 ± 14kg) were utilized to determine the effects of supplemental Zn sulfate on growth, trace mineral status, circulating immune cells, and functional innate immune responses. Steers were stratified by weight and implanted with a Component E-S with Tylan implant (Elanco Animal Health, Greenfield, IN) on day 0. Dietary treatments included: control (CON; no supplemental Zn), Zn100 (100mg supplemental Zn/kg DM), and Zn150 (150mg supplemental Zn/kg DM). Analyzed dietary concentrations of Zn were 58, 160, and 207mg Zn/kg DM, respectively. On days 13 and 57, blood from nine steers per treatment was collected for immune analyses (cell phenotyping and response to stimulus). On day 16, implant abscesses were evaluated by palpation and visual appraisal. Sixty percent of steers had abscesses; however, there were no differences in abscess prevalence due to treatment (P = 0.67). Data were analyzed as a split-plot design using the Mixed procedure of SAS 9.4 (Cary, NC) with effects of dietary treatment, abscess, and their interaction. There was a tendency (treatment × abscess; P ≤ 0.09) for steers without abscesses to have greater average daily gain (ADG; treatment × abscess P = 0.06) and gain:feed (G:F; treatment × abscess P = 0.09) from d 14 to 27 in CON and Zn100 while within Zn150 steers without abscesses tended to have lesser ADG and G:F than abscessed steers. There were no other treatment × abscess effects for growth performance, but steers with abscesses tended to have decreased final body weight (P = 0.10) and overall G:F (days 0 to 57; P = 0.08). There was no interaction of treatment and abscess on immune cell populations on days 13 or 58 (treatment × abscess P ≥ 0.11). On day 13, Zn150 steers had increased CD45RO + gamma delta (P = 0.04) T cells. Abscessed steers had increased CD21 + B cells (P = 0.03) and tended to have increased CD21 + (P = 0.07) and CD21 + MHCIIhi (P = 0.07) B cells in circulation. This study shows zinc supplementation and implant abscesses can alter the immune system and growth performance of growing beef steers.

Effect of dietary treatments on performance, oocysts shedding and lesion scores in broiler chickens experimentally challenged with Eimeria infection

Although anticoccidials effectively control coccidiosis, a needed reduction in the reliance on antimicrobials in animal production leads to the exploration of alternative compounds. The present study aimed to test five different dietary treatments to counteract the negative impact of coccidiosis on broiler chickens’ health and performance. One-day-old male Ross 308 broilers (n = 960) were randomly assigned to one of eight treatments, with six cages per treatment (20 birds/cage). To the diet of the broiler chickens of treatments (Trt) 1–5, a synbiotic was added from d0-10. From d10–28, birds of Trt1 and Trt2 were fed synbiotics, whereas birds of Trt3 were fed diets with glutamine, and birds of Trt4 and Trt5 were fed diets with a combination of β-glucans and betaine. From d28-35 onwards, birds of Trt1 were fed a diet with a synbiotic, whereas birds of Trt2-4 received diets with glutamine, and birds of Trt5 were fed a non-supplemented diet. Birds of the positive control group (PC; Trt6) were fed a standard diet supplemented with an anticoccidial (Decoquinate). The challenged negative control (NCchall; Trt7) and non-challenged negative control (NC) Trt8 were fed a standard diet without anticoccidial or other dietary treatment. At 7 days (d) of age, all birds were inoculated with 1 023, 115, and 512 sporulated oocysts of E. acervulina, E. maxima, and E. tenella respectively, except for Trt8. Body weight gain (BWG), feed intake (FI), and feed conversion ratio (FCR) were assessed for each feeding phase (d0-10, d10-28 and d28-35) and overall experimental period (d0-35). Oocyst shedding, Eimeria lesion scores, caecal length and relative weight were assessed at d13, d22, d28 and d35. Additionally, oocyst shedding was determined at d9 and d17. Litter quality was evaluated at d27 and d34, and footpad lesions at d34. During the starter (d0-10) and finisher (d28-35) periods, performance did not differ between the treatments. During the grower period (d10-28), Trt6 (PC) and Trt8 (NC) chickens had the highest BWG of all treatments (P < 0.001). Dietary treatment had no effect on litter quality and severity of footpad lesions. In the PC group (Trt6) low oocyst excretion and lesion scores were found. When comparing Trt1-5 with NCchall (Trt7), none of the treatments significantly reduced oocyst output nor lesion scores. In conclusion, in this experiment none of the dietary treatments performed similar or better compared to the PC group (Trt6) regarding performance or reducing Eimeria oocyst shedding or lesion scores.

Influence of low-level tannin supplementation on comparative growth performance of Holstein and Angus × Holstein cross calf-fed concentrate-based finishing diets for 328 d.

The objective of the current study was to evaluate the effects of tannin and monensin supplementation in feedlot diets and breed (Holstein vs. Angus × Holstein) on growth performance, energetic efficiency, and carcass characteristics. Eighty purebred Holstein calves (HOL; initial body weight (BW) = 130 ± 5kg) and 80 Angus × Holstein calves (AXH; initial BW = 129 ± 6kg) were blocked by initial BW and randomly assigned to 40 pens. Dietary treatments consisted of a steam-flaked corn-based diet supplemented with (1) no feed additive (CON); (2) 30mg of monensin/kg of dry matter (DM; MON; Rumensin 90, Elanco, Greenfield, IN); (3) 1.5g tannin)/kg of DM (TAN; ByPro, 70% condensed tannin, SilvaFeed, Indunor, S.A., Buenos Aires, Argentina); (4) M + T, the combination of MON plus TAN dietary treatments. Data were analyzed as a randomized complete block in a 2 × 4 factorial arrangement of treatments, using pens as experimental units. There were no interactions (P > 0.05) between feed additives and breed. Supplemental MON increased (P ≤ 0.04) initial 112-d BW and gain efficiency. However, there were no dietary treatment effects (P > 0.10) on overall growth performance. Monensin supplementation decreased (P = 0.04) minimum daily ruminal temperature compared with other dietary treatments during July, but TAN did not affect ruminal temperature. Holstein steers had greater (P = 0.04) overall DM intake compared with AXH, with no difference (P = 0.19) in overall ADG, leading to increased (P < 0.01) gain efficiency for AXH compared with HOL. Dietary net energy for maintenance and gain, based on growth performance, were greater (P ≤ 0.01) for AXH vs HOL. Compared with HOL, AXH steers had greater (P ≤ 0.01) carcass weight, dressing percentage, kidney, pelvic, and heart fat, 12th rib fat thickness, longissimus area, and preliminary yield grade. Holstein steers had lower (P ≤ 0.04) minimum average ruminal temperature during June compared with AXH, with no differences (P ≥ 0.14) between breeds during July or August. Results indicate that feed additives did not appreciably affect steer growth performance and carcass characteristics, but crossbred AXH steers had greater growth performance, efficiency of dietary energy utilization, and carcass quality measures compared with HOL. This study observed a reduction (4.7%) in maintenance energy expenditure in AXH compared with HOL, implying in maintenance energy coefficient of 0.086 vs 0.082 for HOL and AXH, respectively.

Practical implications of lowering dietary starch content on waste management in recirculating aquaculture systems operated with drum filtration or sedimentation in yellowtail kingfish (Seriola lalandi)

Dietary starch negatively affects faecal removal efficiency by sedimentation in yellowtail kingfish (Seriola lalandi). In general, research on waste management in recirculating aquaculture systems (RAS) is conducted on solid removal by sedimentation. However, most commercial farms operate with screen filtration. Compared to sedimentation, where the efficiency of removed faeces depends on faecal particle size and density, faecal removal by screen filtration is based on particle size and its stability. Accordingly, this study investigated the effect of dietary starch level on solid waste loading and faecal removal efficiency by different solid removal techniques, namely drum filtration and sedimentation. This was tested in six individual operating RAS over an experimental period of 47 days. The experimental period was divided into two consecutive phases (Phase 1 and Phase 2). During Phase 1 (42 days), the six independent RAS were operated with drum filtration, while during Phase 2 (5 days), the same RAS were operated with sedimentation. Two experimental diets, one with low starch (LS; 0% gelatinized wheat flour inclusion) and one with high starch (HS; 20% gelatinized wheat flour inclusion) levels, were formulated to test the effect of dietary starch level. HS diet negatively affected the apparent faecal waste production, apparent faecal removal efficiency by sedimentation, and the apparent amount of non-removed faeces. No dietary treatment effect was observed when RAS were operated with drum filtration. However, to achieve similar apparent faecal removal efficiency by drum filtration, the backwash frequency was on average 110% higher at HS RAS compared to LS RAS. This is likely to be related to both an increased apparent faecal waste production and the tendency for increased clogging of the drum filter screen at HS RAS throughout the experimental period. Overall, lowering dietary starch level has the potential to reduce solid loading (sedimentation) or improve drum filter performance (water usage) in RAS for yellowtail kingfish.

Reducing dietary protein and supplementation with starch or rumen-protected methionine and its effect on performance and nitrogen efficiency in dairy cows fed a red clover and grass silage–based diet

The increasing cost of milk production, in association with tighter manure N application regulations and challenges associated with ammonia emissions in many countries has increased interest in feeding lower crude protein (CP) diets based on legume silages. Most studies have focused on alfalfa silage, and there is a lack of information on low CP diets based on red clover silage. Our objectives were to examine the effects of dietary CP content and supplementing a low CP diet with dietary starch or rumen-protected Met (RPMet) on the performance, metabolism, and nitrogen-use-efficiency (NUE; milk N output/N intake) in dairy cows fed a red clover and grass silage-based diet. Fifty-six Holstein-Friesian dairy cows were blocked and randomly allocated to 1 of 4 diets over a 14-week feeding period. Diets were based on red clover and grass silages at a ratio of 50:50 (dry matter (DM) basis) and were fed as a total mixed ration, with a forage-to-concentrate ratio of 53:47 (DM basis). The diets were formulated to supply a similar metabolizable-protein (MP) content, and have a CP concentration of 175 g/kg DM (CON), or 150 g/kg DM (LP = low protein), or LP supplemented with additional barley as a source of starch (+ 64 g/kg DM; LPS) or RPMet (+ 0.3 g/100 g MP; LPM). At the end of the 14-week feeding period, 20 cows (5 per treatment) continued to be fed the same diets for a further 6 d, and total urine output and fecal samples collected. We observed that dietary treatment did not affect DM intake, with a mean of 21.5 kg/d, however, there was an interaction between diet and week with intake being highest in cows fed LPS in wk 4 and CON in wk 9 and 14. Mean milk yield, 4% fat corrected milk and energy corrected milk were not altered by treatment. Similarly, we found no effect of dietary treatment on milk fat, protein or lactose content. In contrast, milk and plasma urea concentrations were highest in cows fed CON. The concentration of blood plasma β-hydroxybutyrate was highest in cows receiving LPM and lowest in LPS. Apparent NUE was 28.6% in cows fed CON, and was higher in cows fed any of the low protein diets (LP, LPS or LPM) with a mean value of 34.2%. The sum of milk fatty acids with a chain length below C16:0 was also highest in cows fed CON. We observed that dietary treatment did not affect the apparent whole-tract nutrient digestibility of organic matter, N, neutral detergent fiber and acid detergent fiber, with mean values of 0.785, 0.659, 0.660 and 0.651 kg/kg respectively, but urinary N excretion was approximately 60 g/d lower in cows fed the low CP diets compared with CON. We conclude that reducing the CP content of red clover and grass silage-based diets from 175 to 150 g/kg DM while maintaining MP supply did not affect performance, but reduced the urinary N excretion and improved NUE, and that supplementing additional starch or RPMet had little further effect.

Timing of dietary zinc additions during gestation for improved piglet survival.

The objectives of this study were to determine a practical approach to feeding elevated dietary zinc (Zn) to gestating sows in a commercial setting and to confirm preweaning mortality could be reduced by feeding high Zn to sows during different periods of gestation. The study was conducted at a commercial sow farm in the upper Midwest. Mixed parity sows (n = 267) over three consecutive weekly farrowing groups (sows farrowing within 1wk) were assigned randomly to one of the three dietary treatments within parity. Treatments consisted of: (1) control sows fed a corn-soybean meal diet containing 206mg/kg total supplemental Zn supplied by zinc hydroxychloride; (2) breed-to-farrow: as control + 147mg/kg supplemental Zn as ZnSO4 (353mg/kg total supplemental Zn) fed from 5 d after breeding to farrowing; and (3) day 110-to-farrow: as control fed from breeding to farrowing + 4,079mg/kg supplemental Zn as ZnSO4 (4,285mg/kg total supplemental Zn) starting day 110 of gestation until farrowing. At farrowing, individual piglets were weighed and identified within 12h of birth. Data were analyzed using PROC GLIMMIX of SAS and the model considered the fixed effect of dietary treatment and random effect of farrowing group. Dietary treatments did not affect number of total pigs born per litter. For breed-to-farrow sows, there was an increase in the percentage of pigs born alive compared to sows fed the control and day 110-to-farrow treatments (P < 0.001). The number of stillborn pigs expressed as a percentage of total litter size at birth decreased for breed-to-farrow sows (P < 0.001) compared with control or day 110-to-farrow sows. Mortality of low birth weight piglets from birth to weaning did not differ among dietary treatments (P = 0.305); however, a trend for decreasing post-natal mortality (P = 0.068) of normal birth weight pigs was observed for pigs born to sows fed elevated Zn 5 d before farrowing. In conclusion, feeding elevated Zn to sows throughout gestation increased the proportion of pigs born alive suggesting that elevated gestational Zn intake makes piglets more robust to endure the stresses of farrowing and decreases intrapartum mortality. Under the conditions of this study, elevated Zn intake of sows did not influence piglet post-natal survival. However, feeding high zinc throughout gestation may decrease piglet mortality during the parturition process.

PSVI-28 The Effects Supplementing Tannin Blend on Growth Performance, Energetic Efficiency, and Carcass Characteristics of Calf-Fed Steers

Abstract Objective of the current study was to evaluate the effects of tannin supplementation on cattle growth performance, energetic efficiency, and carcass characteristics of calf-fed steers. One hundred and sixty dairy steer calves with initial body weight (IBW) of 129.85 ± 3 kg, were blocked by IBW and randomly assigned to 40 pens (4 steers/pen; 10 pens per dietary treatment). Dietary treatments were: 1) Control (no additives); 2) MON (30 mg/kg monensin); 3) TAN (15 g/kg ByPRO; 70% condensed tannin; Silvateam USA, Tontitown, AR); and 4) MON+TAN (30 mg/kg monensin + 15 g/kg ByPRO). All steers were fed a similar steam-flaked corn-based diet (63.5% steam-flaked corn, 12.0% hay, 17.5% of dry distillers grains with solubles, 4.0% cane molasses, and 3.0% vitamin/mineral supplement). All cattle were slaughtered after 328 days of feed. There were no effects (P ≥ 0.13) of dietary treatment on final BW (615 ± 22 kg), overall average daily gain (1.48 ± 0.07 kg/day), overall dry matter intake (7.93 ± 0.39 kg/day), overall gain to feed ratio (0.187 ± 0.07), and overall observed vs. expected net energy for maintenance and gain (1.00 ± 0.03 and 1.00 ± 0.04, respectively). However, cattle receiving MON or MON+TAN supplementation increased (P ≤ 0.04) BW and gain to feed ratio in the first 112 days on feed compared with cattle in the control treatment. Moreover, cattle in the 2 dietary treatments receiving monensin supplementation tended (P ≤ 0.09) to increase average daily gain and gain to feed ratio on the first 112 days on feed compared with cattle in the control treatment. There were no effects (P ≥ 0.22) of feed additive supplementation on hot carcass weight (380.7 ± 14.7 kg), dressing percentage (61.83 ± 1.05%), kidney, pelvic, and heart fat (3.32 ± 0.19%), backfat thickness (0.73 ± 0.12 cm), longissimus muscle area (83 ± 4.83 cm2), marbling score (494 ± 48), and calculated yield grade (2.94 ± 0.24). Moreover, there were no effects (P ≥ 0.55) of dietary treatment on percent of liver abscess incidence, regardless of diet, calf-fed steers in the current study had 3.75% of liver with abscess.

PSVI-21 Effects of Calcium Salts of Soybean Oil Supplementation to Nellore Heifers During Second and Third Trimesters of Gestation and Offspring Sex on Milk Production and Performance of the Offspring

Abstract The study aimed to evaluate the effects of supplementing calcium salts of soybean oil to Nellore heifers during the second and third trimesters of gestation and offspring sex on cow productivity and their male and female offspring growth. Forty-eight pregnant Nellore heifers [body weight (BW) = 387 ± 38.4 kg] were assigned to this experiment at day 123 ± 13 of gestation. All heifers were conceived during the same fixed-time artificial insemination protocol at 14 and 24 months of age. Heifers were randomly used in a completely randomized block design with a 2 × 2 factorial treatment arrangement, consisting of supplementing or not (CON) calcium salts of soybean oil (CSSO; 3 g/kg of BW; Table 1) and the sex of the offspring (male or female), totaling four treatments and twelve reps per treatment. Throughout the experimental period, heifers were maintained in a pasture composed of Brachiaria brizantha cv.Marandu. After birth, all animals remained under the same pasture conditions and received the same supplementation until weaning. Data were analyzed using the MIXED procedure of SAS and heifer as the experimental unit. Treatment × offspring sex interaction was not detected (P &amp;gt; 0.36) for any of the variables evaluated. Calves born from heifers supplemented with CCSO were 2 kg heavier (P = 0.03) at birth and 5 kg heavier (P = 0.03) at 120 days of age compared with calves born from CON heifers. At weaning (210 days), no dietary treatment effects were observed (P = 0.17) in offspring BW. Male offspring were 3.5 kg, 9 kg, and 12 kg heavier (P ≤ 0.01) at birth, day 120, and at weaning, respectively, compared with female offspring (Table 2). Throughout the experiment, male offspring gained 0.040 kg more daily (P = 0.01) than female offspring. The female offspring had 0.1 thicker subcutaneous fat per 100 kg of BW (P = 0.02) than the male offspring. Heifer milk production was not impacted (P &amp;gt; 0.10) by the dietary treatments or sex of the offspring in any of the periods evaluated (days 30 and 210; Table 3). Hence, supplementing CSSO to Nellore heifers during the second and third trimester of gestation altered offspring BW up to 120 days after birth, suggesting programming effects on postnatal offspring growth resultant from the CSSO treatment. Male offspring were heavier from birth to weaning compared with female offspring. These outcomes indicate that supplementing CSSO to Nellore heifers during pregnancy might be a feasible alternative to optimize offspring productivity, and carcass merit in grazing systems.

213 Increasing Growth Performance by Attenuating the Transportation Stress Response in Nursery Pigs Through L-Tryptophan Supplementation

Abstract Weaning and transport stress impairs intestinal function and reduces nutrient absorption leading to reduced growth performance and feed efficiency. The objective of this study was to eliminate or reduce short- and long-term, transport-induced reductions in feed efficiency and growth by providing supplemental Tryptophan (Trp) above NRC (2012) pre- and/or post-weaning. A total of 480 pigs were blocked by sex, ancestry, and body weight (BW) and used in a RCB design with a 2x2x2 factorial arrangement of pre-weaning treatment (oral gavage of Trp at 0.35, 0.45, and 0.55 g/d (increasing every 5d) pre-weaning or control), transport (transported or not at weaning), post-weaning nursery treatment (1X or 2X NRC Trp). At farrowing pigs were blocked by sex, within litter, and randomly assigned to either a pre-wean Trp or control treatment, where Trp supplementation began on d 5 post-farrowing and stopped at weaning. Post-weaning Trp supplementation included a 3 d oral gavage of Trp and 2X Trp in the diet for the entire 42 d nursery period. At weaning, all pigs were blocked by sex, weaning weight and pre-wean treatment and randomly assigned to transport and post-wean treatments. Pigs were fed four nursery phases with diets containing 1X or 2X NRC recommended concentrations of Trp. There were 10 pens/trt with 6 pigs/pen (equal barrows and gilts). Individual BW were determined every 5 d pre-weaning and every 7 d post-weaning along with pen feed intakes. Data were analyzed as a RCB using GLM procedure in SAS 9.4 with fixed effects of pre-wean dietary treatment, transport treatment, and post-wean dietary treatment, the interactions, and random effect of replicate. Pre-weaning Trp supplementation had no effect on pre-weaning growth performance. A 3-way interaction of pre-wean treatment x transportation x post-wean treatment was observed for overall nursery BW (P = 0.0148) and ADG (P = 0.0175). This interaction was the result of post-weaning Trp supplementation increasing BW and ADG in all pigs, except for transported pigs that did not receive Trp pre-weaning. While there were 2-way interactions of pre-wean treatment x post-wean treatment on ADFI at week 1 ( P= 0.0123) and week 6 (P = 0.0297) and a 3-way interaction of pre-weaning treatment x transportation x post-weaning treatment at week 2 (P = 0.0092), there were no consistent or overall effects on overall ADFI or G:F. Tryptophan improves transported pigs BW and ADG when supplemented pre- and post-weaning but does not benefit transported pigs when only supplemented post-weaning, suggesting transportation induced reductions in BW and ADG can be mitigated by supplementing Trp prior to and following transportation.

207 Effects of Crude Protein and Non-Essential Amino Acids Supplementation on Growth Performance and Gut Health of Nursery Pigs

Abstract This study investigated the effect of crude protein (CP) and non-essential amino acids (NEAA) supplementation on growth performance and gut health of nursery pigs. Weaned pigs (n = 90; 22 days old; 7.5 ± 0.7 kg BW; AGPIC 415 × Camborough) barrows and gilts, were distributed in a randomized complete block design (BW as block) to three dietary treatments fed for 14 days: 1) 24% CP, 2) 18% CP, and 3) 18% CP + NEAA, including 5 g/kg L-arginine and 10 g/kg L-glutamate + L-glutamine (AminoGut, Ajinomoto, São Paulo, Brazil). There were 10 replicates per treatment and three pigs per pen. A corn-soybean meal-based diet was formulated to have 3,400 kcal/kg of metabolizable energy and 1.45 g/kg of standardized ileal digestible lysine. Crystalline amino acids, L-Lys, L-Thr, DL-Met, L-Trp, L-Val, L-Ile, L-His, and L-Leu were used (if necessary) to satisfy the ideal amino acid profile according to the Brazilian Tables for Poultry and Swine (Rostagno et al., 2017). On day 14, pigs were weighed and then euthanized to collect duodenum, jejunum, and ileum tissue. Growth performance, diarrhea incidence, intestinal morphology, goblet cells, and Peyer’s patches were evaluated. Data were analyzed using the Mixed procedure in SAS 9.4 and means were compared by Tukey’s test. Pigs fed 24% CP diet had improved (P &amp;lt; 0.05) G:F compared with 18% CP and 18% CP + NEAA (Table 1). There was no effect (P &amp;gt; 0.05) of dietary treatments on ADFI, ADG, BW, and diarrhea incidence. In the duodenum, pigs fed 18% CP + NEAA diets had greater (P &amp;lt; 0.05) villus height compared with the 24% CP and 18% CP (427 to 381 and 383 µm). Moreover, goblet cells proportion in pigs fed 24% CP and 18% CP + NEAA diets were greater (P &amp;lt; 0.05) than that of 18% CP (53.2 and 53.4 to 45.3%). In the jejunum, pigs fed 18% CP + NEAA diet had reduced (P &amp;lt; 0.05) crypt depth than those fed 24% CP (161 and 141 µm), whereas pigs fed 18% CP presented intermediate results (144 µm). In the ileum, pigs fed the 24% CP diets presented a greater (P &amp;lt; 0.05) number of Peyer’s patches compared with 18% CP and 18% CP + NEAA (48 to 38 and 41 units). In conclusion, nursery pigs fed 24% CP diets presented improved G:F compared with those fed 18% CP or 18% CP + NEAA. However, pigs fed the 18% + NEAA diets presented better gut health compared with 24% CP or 18% CP.

256 Evaluation Calcium and Phosphorus Ratios in the Presence of Phytase on Performance and Whole-Body Bone Mineralization in Growing Pigs

Abstract The objective of this study was to evaluate the effects of dietary calcium and phosphorus ratios in the presence of super dose phytase on grower pigs growth performance and bone mineral density. In two replicates, a total of 48 mixed sex pigs (26.7 kg BW) were allotted by BW and sex into individual pens across 3 dietary treatments (16 pigs/treatment) for 28 days. All diets contain phytase at 1,500 FTU/kg of complete feed and the three diet treatments were formulated with differing levels of Ca to achieve 0.7, 1.1 and 1.5 total Ca:total P. All diets were formulated to be isocaloric and isonitrogenous and ratios were achieved by vary limestone and sand. Pig BW and feed disappearance were recorded at the start (d 0) and end (d 28) of the study to calculate ADG, ADFI and G:F. On day 28, all pigs were euthanized to determine whole body bone, foot, rib, femur and tibia bone mineral density via dual x-ray absorptiometry. Data were analyzed with pen as the experimental unit, fixed effect of dietary treatment, sex and their interaction, and initial BW block and repartition as random effects. Differences were determined significant at P ≤ 0.05. Pig ADG was increased in the 1.1 verses 0.7 and 1.5 Ca:P diets (1.01, 0.95 and 0.95 kg/d, respectively, P = 0.046). End body weight was not different in the 0.7, 1.12 and 1.5 Ca:P treatments (53.5, 54.8 and 53.1 kg, respectively, P = 0.106). Diet Ca:P ratio did not alter ADFI or G:F. Whole body, tibia and femur bone mineral density was increased by 110% in 1.5 verses 0.7 Ca:P fed pigs, with bone mineral density being intermediated in the 1.1 Ca:P diets. Whole body (0.740, 0.752, 0.797, g/cm2, for 0.7, 1.1 and 1.5 Ca:P respectively, P = 0.033). For 0.7, 1.1 and 1.5 Ca:P femurs, bone mineral density was 0.463, 0.498 and 0.516, respectively, P = 0.034). Dietary treatment did not alter whole foot or 10th rib bone mineral densities (P &amp;gt; 0.05). Sex did not affect pig performance, but gilts had a 9% increase in bone mineral content. In conclusion, formulating dietary Ca:P in the presence of super dosing phytase at 1.1:1 total Ca:P resulted in the best ADG, but a ratio of 1.5:1 had the greatest bone mineral density.

255 Evaluation of Growth Performance and Bone Mineral Density in Grower Pigs Fed Phosphorus, Calcium, and Vitamin D Deficient Diets

Abstract The objective of this study was to evaluate the effects of phosphorus, calcium and vitamin D deficient diets on growth performance and bone mineral density (BMD) in grower pigs. In two replicates, a total of 80 mixed sex pigs (26.7 kg BW) were allotted by BW and sex into individual pens across 5 dietary treatments (16 pigs/trt) for 28 days. Diets were: 1) Positive control (PC) diet containing monocalcium phosphate and no phytase, 2) PC diet containing phytase 1,500 FTU of Optiphos 2500, 3) Diet deficient in phosphorus (no monocalcium phosphate or phytase), 4) Calcium deficient diet (as diet 2 with no limestone), and 5) Diet deficient in vitamin D as diet 2 containing no added vitamin D. All diets were formulated to 3,297 kcal/kg ME, 1.15% SID Lys and contain the same AA:Lys ratios. Total Ca was formulated to be 0.76, 0.53, 0.45, 0.20 and 0.53%, with available P at 0.32, 0.32, 0.07, 0.32 and 0.32% respectively, for Treatments 1-5. Vitamin D was formulated to be at 154 IU/kg diet for Treatment 1-4. Pig BW and feed disappearance were recorded at the start and end of the study to calculate ADG, ADFI and G: F. On day 28, serum was collected, and all pigs euthanized to determine whole body bone, foot, rib, femur, and tibia BMD via dual x-ray absorptiometry. Data were analyzed with pen as experimental unit, fixed effect of dietary treatment, sex and their interaction, and initial BW block and repartition as random effects. Diet by sex interactions not observed (P &amp;gt;0.05). Compared with either Treatment 1 and 2, P and Ca deficient diets reduced ADG (0.96, 1.01, 0.80 and 0.91 kg/d, respectively (P &amp;lt; 0.001). The ADFI did not differ across dietary treatments. Vitamin D deficient pigs did not differ from either control treatments. Feed efficiency was different between treatments 1-4 (0.51, 0.53, 0.47 and 0.50, respectively, P &amp;lt; 0.001). Whole body BMD was reduced in the P and Ca deficient diets compared with Treatment 1 and 2 (0.582, 0.678, 0.803 and 0.758 g/cm2, respectively, P &amp;lt; 0.001). Similar results for 10th rib, femur, and tibia bones (P &amp;lt; 0.001). Vitamin D deficient diets reduced whole body and tibia BMD compared with Treatment 1 by 1.5% (P &amp;lt; 0.05). Gilts had greater whole body (0.762 vs. 0.703 g/cm2) and tibia (0.448 vs. 0.408 g/cm2) BMD compared with barrows (P &amp;lt; 0.05). In conclusion, dietary phytase provided similar performance and BMD to that of non-phytase control diet. Feeding P and Ca deficient diets for 28 days reduced pig growth and bone density, with P diets having more severe reductions. Further, while there was a slight reduction in growth there were no detrimental effects on bone mineralization in pigs fed vitamin D deficient diets.

The effect of teff (Eragrostis tef) hay inclusion on feed intake, digestibility, and milk production in dairy cows

Teff (Eragrostis tef) is a drought-tolerant, multi-harvest, high-quality summer forage crop. We conducted a study aiming at assessing the effect of replacing wheat hay with teff hay in diets on the feed intake, digestibility, and lactational performance of dairy cows. Thirty-four multiparous (≥3rd parity) Israeli Holstein Friesian dairy cows averaging (± SD) 182 days in milk ± 8 days in milk, 45 kg/d ± 4.8 kg/d of milk yield, and a body weight of 647.1 kg ± 51 kg at the beginning of the study were recruited to a 6-week feeding trial. Cows were randomly divided into two balanced groups based on parity, days in milk, and milk yield. Cows were subjected to two low-roughage dietary treatments (~30% roughage): a control wheat hay-based diet and a teff hay-based diet. Production performances, dry matter intake, and nutrient digestibility were measured. Milk samples were analyzed for their composition and fatty acids profile. Blood samples were used to measure metabolite concentrations. The statistical model included fixed effects of dietary treatments, time, and random effects of cows nested in treatment. Production data and feed intake were analyzed as repeated measures using a covariance structure. Dietary treatments did not affect dry matter intake (26 kg/d). However, the teff-fed cows demonstrated higher crude protein digestibility than control cows (61.9% vs. 59.2%). Dietary teff inclusion increased milk yield by 1.5 kg/d. Polyunsaturated fatty acids and omega-3 fatty acids profiles in milk were greater in the teff cows than in the control cows (4.77 g/100 g vs. 4.36 g/100 g and 3.71 g/100 g vs. 3.43 g/100 g, respectively). Non-esterified fatty acids, beta-hydroxybutyrate, and blood urea nitrogen concentrations in circulation were higher in the control group than in the teff group. The acetic-to-propionic-acid ratio in the rumen fluid was higher in control cows than in teff cows (2.90 vs. 2.43). However, the ruminal ammonia-N concentration was higher in the teff cows than in the control cows (18.5 mg/dL vs. 15.8 mg/dL). In conclusion, teff hay inclusion in the rations of high-producing dairy cows increased milk yield, which could be attributed to improved crude protein digestibility and energy partition to production.