Feed Intake Research Articles

Phytosterol supplementation enhances the growth performance, feed utilization, antioxidant status and glucose metabolism of juvenile largemouth bass (Micropterus salmoides) fed a high-starch diet

IntroductionPrevious studies found that phytosterols could influence growth performance, feed utilization and lipid metabolism as well as improve the antioxidant capacity of animals.MethodsTo investigate the effects of dietary phytosterol supplementation on juvenile largemouth bass (Micropterus salmoides) fed a high-starch diet, a 56- day feedingtrial was conducted with four dietary feeds for juvenile largemouth bass: extruded floating feed isonitrogenous and isoenergetic diets were formulated to contain 10% and 15% α-starch; on the basis of a 15% α-starch diet, two other diets were formulated with supplementation of 0.1% and 0.5% phytosterol, respectively. After the feeding trials, the survival rate, weight gain and specific growth rate, feed conversion ratio, intraperitoneal fat ratio, feed intake, protein efficiency ratio and activities of three digestive enzymes, as well as the concentrations of nine plasma biochemical indices, hepatic enzyme activities and glycogen contents, were measured and calculated, and the data were statistically analyzed.ResultsThe results of the present study showed that the survival rate, weight gain and specificgrowthrates were significantly greater in plants fed high-starch diets supplemented with phytosterols. As the supplemental phytosterol concentration increased, the feed conversion ratio and intraperitoneal fat ratio significantly decreased; the protease and lipase levels in the pyloric zone markedly increased; the plasma cholesterol, triglyceride, glucose, malondialdehyde, aspartate transaminase and alanin transaminase levels significantly decreased; the glucokinase and pyruvate kinase levelsmarkedly increased; and the hepatic glycogen content significantly decreased.DiscussionIn summary, dietary phytosterol supplementation promoted the growth performance, feed utilization and antioxidant status of juvenile largemouth bass fed a highstarch diet; enhanced glucose utilization and metabolism; and alleviated the negative stimulation of glycemia stress in M. salmoide fed a high-starch diet.

Impact of Nanoencapsulated Rosemary Essential Oil as a Novel Feed Additive on Growth Performance, Nutrient Utilization, Carcass Traits, Meat Quality and Gene Expression of Broiler Chicken

This study evaluated the effect of free and nanoencapsulated rosemary essential oil (REO) as an antibiotic alternative in broiler diets on growth performance, nutrient digestibility, carcass traits, meat quality and gene expression. Four hundred twenty day-old commercial broiler chicks (VENCOBB) were randomly allocated to seven dietary treatments, each having four replicates of fifteen chicks. The dietary treatments comprised control (CON) fed a basal diet only, AB (basal diet + 10 mg enramycin/kg), CS (basal diet + 150 mg chitosan nanoparticles/kg), REOF100 and REOF200 (basal diet + 100 mg and 200 mg free REO/kg, respectively), and REON100 and REON200 (basal diet + 100 mg and 200 mg nanoencapsulated REO/kg, respectively). Overall (7–42 d), REON200 showed the highest (p < 0.001) body weight gain (1899 g/bird) and CON had the lowest gain (1742 g/bird), while the CS, REOF100 and REOF200 groups had a similar gain, but lower than that of the AB and REON100 groups. Feed intake was not affected by dietary treatments. Overall, the feed efficiency increased (p = 0.001) by 8.47% in the REON200 group and 6.21% in the AB and REON100 groups compared with the CON. Supplementation of REO improved (p < 0.05) dry matter and crude protein digestibility, with the highest values in REON100 and REON200. Ether extract, crude fiber, calcium and phosphorus digestibility values showed no difference among the groups. The dressing, breast, thigh % increased (p < 0.05) and abdominal fat % decreased (p < 0.001) more in the REON200 group than with other treatments and CON. In breast meat quality, water holding capacity and extract reserve volume increased (p < 0.05) while drip loss and cholesterol content decreased (p < 0.05) in REON100 and REON200. No change was observed in the breast meat color among dietary treatments and CON. The REON100 and REON200 groups had reduced (p < 0.05) meat lipid peroxidation as depicted by the decreased levels of TBARS, free fatty acids and peroxide value compared to other treatments and CON. The expression of the Mucin 2, PepT1 and IL-10 genes was upregulated (p < 0.001) and TNF-α downregulated (p < 0.001) by dietary addition of REO particularly in the nanoencapsulated form compared with the CON. In conclusion, nanoencapsulated REO, especially at 200 mg/kg diet, showed promising results as an antibiotic alternative in improving the performance, nutrient digestibility, carcass traits, meat quality and upregulation of growth and anti-inflammatory genes.

Evaluation of clove powder as a feed additive on the performance, carcass traits, and internal organ weights of broiler chickens

This study investigated clove powder as a feed additive on the performance, carcass traits, and internal organ weights of broiler chickens. A total of 160-day-old (Arbo acre) broiler chickens were utilized for the study. Four diets, designated as T1, T2, T3 and T4, were formulated. T1 served as the control with no clove powder, while T2, T3 and T4 had clove powder included at 100 g, 200 g, and 300 g/100 kg of feed, respectively. The birds were distributed into 4 treatment groups, each comprising 4 replicates of ten birds each. Each treatment was randomly assigned one of the treatment diets in a completely randomized design. Significant differences (P<0.05) were observed in the final weight, weight gain, and feed intake of the birds at the starter phase. Birds in the T4 group recorded the highest values (P<0.05) for the three parameters assessed. T1 had the lowest values for the parameters. There was no significant difference in the feed conversion ratio of the birds across treatments. T4 had the lowest but non-significant feed conversion ratio. In the finisher phase, the result of the performance of the birds followed the same trend. Final weight, weight gain, and feed intake values were observed to be highest (P<0.05) in birds fed a T4-based diet. The feed conversion ratio also indicated no significant (P>0.05) difference across treatments. Live weight, dressed weight, dressing percentage, primal cuts (thigh, breast, drumstick, back, and wing) and abdominal fat indicated significant differences (P<0.05) across treatments. No significant differences (P>0.05) were observed in the internal organs of the chickens. It was concluded that incorporating clove powder up to 300 g in the broiler chicken diet improved growth performance and carcass traits without adverse effects on the internal organs of the chickens.

Hourly Feeding Regime of Modern Genetics Lactating Sows: Enhancing Productive Performance, Welfare, and Piglet Growth in Smart Farm-Based Systems

Effective management of lactating sows significantly influences various aspects of swine production. This study compared the impact of an hourly feeding regime and a five-times-daily feeding regime on the productive performance, body condition, and welfare of lactating sows, as well as on the growth performance of their offspring. Twenty-eight lactating sows (Landrace × Yorkshire) were divided into two groups: Group 1 was fed five times a day, and Group 2 was fed according to an hourly regime. The data were analyzed using independent-samples T-tests and the Mann–Whitney U test using Statistical Analysis System (SAS, 2011, Version 9.3) software. An hourly feeding regime positively affected (p < 0.05) sows’ feed intake and body condition, significantly reducing the days from the weaning-to-estrus interval. Group 1 exhibited significantly higher (p < 0.05) reductions in backfat thickness (BFT) and body condition score (BCS) during the weaning period compared to Group 2. Additionally, significant differences (p < 0.05) were observed in regard to sow body weight loss, feed intake, piglet livability and mortality rate at weaning, sow index, and calculated milk yield. Feeding sows according to an hourly regime positively impacted their productive performance compared to those fed five times daily. No significant differences (p > 0.05) were recorded in regard to the total number of piglets born, live births, mummified piglets, stillbirths, piglet mortality, litter size at weaning, and sow feed conversion ratio (FCR). However, the number of piglets weaned per sow per year (PSY) was numerically higher in Group 2 (p > 0.05). The piglets from Group 2 had significantly higher (p < 0.05) weaning weights and exhibited lower feed intake, greater weight gain, improved average daily gain, and greater litter size weight gain than those from Group 1. Statistically, sows from Group 2 exhibited a higher frequency of standing (p < 0.05), which potentially contributed to the reduction in shoulder skin lesions in sows (p > 0.05). In conclusion, an hourly feeding regime could optimize sow productive performance, body condition, milk yield, welfare, and piglet growth in swine production.

Curcumin’s effects on growth indices, histological scores, blood metabolites, redox state, immunity, and antioxidant-related genes of red tilapia (Oreochromis sp.)

AbstractCurcumin, a polyphenol, targets multiple signaling molecules and shows activity at the cellular level, supporting its various health benefits. Thereafter, the present study examines the effects of different doses of dietary curcumin on growth indices, feed efficiency, serum metabolites, redox (oxidation) status, immunity, histological assessment, and antioxidant-related genes in red tilapia (Oreochromis sp, Oreochromis aureus x O. mossambicus). A total of 1200 red tilapia with an average weight of 19.1±0.03 g were distributed in 12 cement ponds (3×3.5×1m). Each treatment was assigned three pounds (n=100 replicates). For 60 days, fish were fed baseline diets containing 0, 0.4, 0.6, and 0.8 g of curcumin/kg of diet. The treated fish showed increased body weight and SGR (specific growth rate) compared to the T0 group (P<0.05). Curcumin in the diet significantly improved weight gain, percentages, and FCR (feed conversion ratio), with a dose-dependent effect (P < 0.05). Curcumin supplementation showed no influence on feed intake, fish mortality, or survival rate (P >0.05). The curcumin-treated fish groups improved tissue structure in hepatocytes, pancreatic lumens, hepatic blood sinusoids, and intestine tissue layers, particularly the mucosal layer. The T0.8 group had reduced liver enzymes (AST and ALT) and greater total protein and albumin levels (P<0.05). The T0.6 and T0.8 groups showed significantly lower MDA levels than the other groups (P < 0.05). Curcumin groups demonstrated significantly higher antioxidant indices (CAT, GPx, and SOD) compared to the basal diet (P<0.05). Curcumin administration resulted in significant improvements in IgM and lysosome levels (P<0.05). All supplemented groups had considerably (P<0.05) higher levels of SOD, CAT, and GPx mRNA than the control group. Consequently, administering 0.6–0.8 g/kg of curcumin to red tilapia (Oreochromis sp.) diets may improve the fish’s growth, health, tissue composition, and antioxidant response.

Behavioral consistency of competitive behaviors and feeding patterns in lactating dairy cows across stocking densities at the feed bunk

IntroductionHigh feed bunk stocking densities can differentially impact individual dairy cows’ competitive behaviors, feeding patterns, and feed efficiency. Our objective was to manipulate feed bunk stocking densities to evaluate intra-individual behavioral consistency across stocking densities and quantify associations with feed efficiency and production.MethodsThirty-two primiparous (130.7 ± 29.0 days in milk, DIM) and 32 multiparous (111.3 ± 38.3 DIM) lactating Holstein cows were housed with 32 roughage intake control (RIC) bins. Each cow was assigned to share 8 bins with others of the same parity and similar body weight (16 cows/block; 2:1 feed bunk stocking density except during tests). Competition and feeding patterns were evaluated via video and RIC data, respectively, at 3 stocking densities (1:1, 2:1, 4:1 cows/bin) during 1-h tests (2 tests/stocking density; 6 tests/cow) following 2 h feed deprivation. Residual feed intake (RFI) was calculated across the 45-d study as the difference between observed and predicted dry matter intake (DMI) after accounting for known energy sinks. Linear mixed models were used to evaluate the overall impact of test stocking density on competition and feeding patterns. To evaluate intra-individual consistency between stocking densities, individual stability statistic (ISS) scores were computed. Correlational relationships were determined between RFI and ISS scores.Results and dicsussionCows displayed the most competitive behaviors at 2:1 stocking density (p < 0.0001) but experienced the highest rate of contacts per minute of eating time at 4:1 (1:1 vs. 2:1 vs. 4:1: 0.09 vs. 0.95 vs. 1.60 contacts/min; p < 0.0001). Feeding patterns were modulated as stocking density increased; eating rate increased (0.16 vs. 0.18 vs. 0.22 kg/min; p < 0.001) as eating time (40.3 vs. 28.2 vs. 14.6 min; p < 0.001) and DMI decreased (6.3 vs. 5.1 vs. 3.0 kg; p < 0.001). As stocking density doubled, individuals remained consistent (p = 0.018) in time spent near others actively eating and tended to remain consistent in competition behavior and feeding patterns (0.053 ≤ p ≤ 0.094). Between 2:1 and 4:1, cows with higher DMI and milk production were more consistent in first-visit DMI and duration. Feed efficiency was not associated with behavioral consistency across the tests (p ≥ 0.14). Nonetheless, feed bunk stocking density has behavioral implications which should be considered in nutritional management decisions.

Multi-Target Feeding-Behavior Recognition Method for Cows Based on Improved RefineMask

Within the current process of large-scale dairy-cattle breeding, to address the problems of low recognition-accuracy and significant recognition-error associated with existing visual methods, we propose a method for recognizing the feeding behavior of dairy cows, one based on an improved RefineMask instance-segmentation model, and using high-quality detection and segmentation results to realize the recognition of the feeding behavior of dairy cows. Firstly, the input features are better extracted by incorporating the convolutional block attention module into the residual module of the feature extraction network. Secondly, an efficient channel attention module is incorporated into the neck design to achieve efficient integration of feature extraction while avoiding the surge of parameter volume computation. Subsequently, the GIoU loss function is used to increase the area of the prediction frame to optimize the convergence speed of the loss function, thus improving the regression accuracy. Finally, the logic of using mask information to recognize foraging behavior was designed, and the accurate recognition of foraging behavior was achieved according to the segmentation results of the model. We constructed, trained, and tested a cow dataset consisting of 1000 images from 50 different individual cows at peak feeding times. The method’s effectiveness, robustness, and accuracy were verified by comparing it with example segmentation algorithms such as MSRCNN, Point_Rend, Cascade_Mask, and ConvNet_V2. The experimental results show that the accuracy of the improved RefineMask algorithm in recognizing the bounding box and accurately determining the segmentation mask is 98.3%, which is higher than that of the benchmark model by 0.7 percentage points; for this, the model parameter count size was 49.96 M, which meets the practical needs of local deployment. In addition, the technologies under study performed well in a variety of scenarios and adapted to various light environments; this research can provide technical support for the analysis of the relationship between cow feeding behavior and feed intake during peak feeding periods.

Exploring the genetic control of sweat gland characteristics in beef cattle for enhanced heat tolerance

BackgroundThermal stress in subtropical regions is a major limiting factor in beef cattle production systems with around $369 million being lost annually due to reduced performance. Heat stress causes numerous physiological and behavioral disturbances including reduced feed intake and decreased production levels. Cattle utilize various physiological mechanisms such as sweating to regulate internal heat. Variation in these traits can help identify genetic variants that control sweat gland properties and subsequently allow for genetic selection of cattle with greater thermotolerance.MethodsThis study used 2,401 Brangus cattle from two commercial ranches in Florida. Precise phenotypes that contribute to an animal’s ability to manage heat stress were calculated from skin biopsies and included sweat gland area, sweat gland depth, and sweat gland length. All animals were genotyped with the Bovine GGP F250K, and BLUPF90 software was used to estimate genetic parameters and for Genome Wide Association Study.ResultsSweat gland phenotypes heritability ranged from 0.17 to 0.42 indicating a moderate amount of the phenotypic variation is due to genetics, allowing producers the ability to select for favorable sweat gland properties. A weighted single-step GWAS using sliding 10 kb windows identified multiple quantitative trait loci (QTLs) explaining a significant amount of genetic variation. QTLs located on BTA7 and BTA12 explained over 1.0% of genetic variance and overlap the ADGRV1 and CCDC168 genes, respectively. The variants identified in this study are implicated in processes related to immune function and cellular proliferation which could be relevant to heat management. Breed of Origin Alleles (BOA) were predicted using local ancestry in admixed populations (LAMP-LD), allowing for identification of markers’ origin from either Brahman or Angus ancestry. A BOA GWAS was performed to identify regions inherited from particular ancestral breeds that might have a significant impact on sweat gland phenotypes.ConclusionsThe results of the BOA GWAS indicate that both Brahman and Angus alleles contribute positively to sweat gland traits, as evidenced by favorable marker effects observed from both genetic backgrounds. Understanding and utilizing genetic traits that confer better heat tolerance is a proactive approach to managing the impacts of climate change on livestock farming.

Estimation of genetic parameters for maintenance energy requirements and residual feed intake in Nellore cattle.

We estimated heritabilities and genetic and phenotypic correlation estimates for maintenance energy requirements (NEmR), residual feed intake (RFI), growth, carcass and reproductive indicator traits, using data from 41 feed efficiency trials in Brazil, comprising 4381 males and females. Continuous traits were analysed using a linear animal model and threshold traits were analysed using a threshold animal model. The heritability estimates were low for RFI (0.190) and NEmR (0.193); other heritabilities were mainly moderate (growth and carcass traits) or high (sexual precocity traits). The genetic correlation of RFI with NEmR was high (0.701). The genetic correlations of NEmR were low with carcass and reproductive traits, and moderate with growth traits. Thus, selection to improve weaning weight and female sexual precocity indicator traits would not affect maintenance energy requirement. Genetic selection to reduce maintenance energy requirements is feasible and would also reduce DMI and RFI. Selection to improve RFI can be used to identify animals with lower maintenance energy requirements. Long-term selection to reduce RFI and NEmR would have favourable effects on yearling weight, carcass muscle indicator traits and female sexual precocity. Genetic (co)variance component estimates for NEmR, in conjunction with economic values of selection criteria, may be used to develop novel approaches for genetic selection to improve efficiency of beef production.

Effects of high dietary inclusion of Arthrospira platensis, either extruded or supplemented with a super-dosing multi-enzyme mixture, on broiler growth performance and major meat quality parameters

BackgroundThis investigation assessed the effects of high dietary inclusion of Spirulina (Arthrospira platensis) on broiler chicken growth performance, meat quality and nutritional attributes. For this, 120 male broiler chicks were housed in 40 battery brooders (three birds per brooder). Initially, for 14 days, a standard corn and soybean meal diet was administered. Subsequently, from days 14 to 35, chicks were assigned to one of the four dietary treatments (n = 10 per treatment): (1) control diet (CTR); (2) diet with 15% Spirulina (SP); (3) diet with 15% extruded Spirulina (SPE); and (4) diet with 15% Spirulina plus a super-dosing enzymes supplement (0.20% pancreatin extract and 0.01% lysozyme) (SPM).ResultsThroughout the experimental period, both SP and SPM diets resulted in decreased final body weight and body weight gain compared to control (p < 0.001), with the SPE diet showing comparable results to CTR. The SPE diet prompted an increase in average daily feed intake (p = 0.026). However, all microalga treatments increased the feed conversion ratio compared to CTR. Dietary inclusion of Spirulina notably increased intestinal content viscosity (p < 0.010), which was mitigated by the SPM diet. Spirulina supplementation led to lower pH levels in breast meat 24 h post-mortem and heightened the b* colour value in both breast and thigh meats (p < 0.010). Furthermore, Spirulina contributed to an increased accumulation of total carotenoids, n-3 polyunsaturated fatty acids (PUFA), and saturated fatty acids (SFA), while diminishing n-6 PUFA, thus altering the n-6/n-3 and PUFA/SFA ratios favourably (p < 0.001). However, it also reduced zinc concentration in breast meat (p < 0.001).ConclusionsThe findings indicate that high Spirulina levels in broiler diets impair growth due to increased intestinal viscosity, and that extrusion pre-treatment mitigates this effect. Despite reducing digesta viscosity, a super-dosing enzyme mix did not improve growth. Data also indicates that Spirulina enriches meat with antioxidants and n-3 PUFA but reduces α-tocopherol and increases saturated fats. Reduced zinc content in meat suggests the need for Spirulina biofortification to maintain its nutritional value.

Essentiality of dietary cholesterol and its interactions with phospholipid in juvenile slipper lobster (Thenus australiensis)

This study was conducted to verify the essentiality of dietary cholesterol for early juvenile slipper lobster, Thenus australiensis (initial weight 4.50 ± 0.72 g, mean ± SD, CV = 0.16), and to explore the potential for interactions between dietary cholesterol and phospholipid. An 8-week experiment was conducted using six experimental feeds containing three supplemental cholesterol concentrations (0, 0.2 and 0.4% dry matter) at two supplemental phospholipid concentrations (0% and 1.0% dry matter). Dietary cholesterol concentrations of ≥ 0.2% resulted in up to threefold greater weight gain compared to 0% dietary cholesterol, but without any significant main or interactive dietary phospholipid effect. An interaction was observed for lobster survival with lowest survival (46%) recorded for combined 0% cholesterol and 0% phospholipid compared to every other treatment (71–100%). However, all surviving lobsters at 0% dietary cholesterol, regardless of dietary phospholipid level, were in poor nutritional condition. Apparent feed intake (AFI) was significantly higher at dietary cholesterol ≥ 0.2% but was lower for each corresponding dietary cholesterol level at 1% dietary phospholipid. This implied that the feed conversion ratio was improved with supplemental phospholipid. In conclusion, this study confirms the essential nature of dietary cholesterol and that dietary phospholipid can provide additional benefits.

Effect of temporal thermal stress on Penaeus vannamei: Growth performance and physiological plasticity.

The present study evaluated the effect of temporal periods of hypothermia and hyperthermia, followed by an optimal temperature recovery phase on the growth, survival, and physiological response of Penaeus vannamei. Post-larvae were exposed to stress periods for 7 and 14 days at 22 °C and 32 °C each, followed by a recovery phase at 28 °C to complete seven experimental weeks, and were compared with a control group maintained at 28 °C. Weight gain, specific growth rate, feed intake, feed conversion ratio, and survival were weekly determined. Muscle, hepatopancreas, and hemolymph were sampled on the 14th day of the recovery phase for biochemical composition, and antioxidant and digestive enzyme activities determination. The shrimp presented a higher growth rate during short-term hyperthermia in contrast to shrimp under hypothermia that presented compensatory growth after thermal stress when the temperature was restored at 28 °C. Hyperthermia increased 12–13% the feed intake while this was diminished 21–29% by the hypothermia periods. Shrimp undergo metabolic adjustments following thermal stress, with short hypothermia increasing the lipase activity and lipid storage in the hepatopancreas, while short hyperthermia also enhances chymotrypsin activity and leads to higher protein and lipid accumulation. Conversely, prolonged hyperthermia induces greater energy consumption, depleting lipid and glycogen stores, while hypothermia causes scarce mobilization of energy reserves during recovery phase. Antioxidant enzyme activities were not affected by short-thermal stress (7d), while prolonged thermal stress (14d) significantly affected SOD, CAT, and GPx activities. The present study provides important insights into the physiological plasticity of P. vannamei during recovery from thermal stress.

216 Is weaning body weight more important than early post-weaning feed intake? A meta-analysis exploring electronic feeding stations data

Abstract The present meta-analysis investigated the effects of initial voluntary post-weaning feed intake (FI) and weaning body weight (BW) on daily FI and body weight (BW) development in nursery pigs housed in electronic feeding stations (EFS). In total, 18 studies (2006-2017, Trouw Nutrition, The Netherland) were used containing 1,177 mixed-sex pigs weaned at ~25 d (7.3 ± 1.5 kg BW). Studies lasted for 14 d (3 studies;162 pigs), 21 d (3 studies; 154 pigs), 31 d (7 studies; 467 pigs), or up to 38 to 52 d (5 studies; 394 pigs) post-weaning. Pigs were housed in pens with single-space EFS with 10 to 12 pigs/pen. Daily individual FI and BW at different timepoints were determined. Across studies various dietary treatments were applied by EFS with a feed phase change on d 4-8 (13 studies) or d 14 (5 studies). Classes were created with pigs above or below their respective study median on a) cumulative FI over the initial 4 d post-weaning (Fid 0-3; Hfi and Lfi), and b) BW0 (Hbw and Lbw). Mixed models were used to analyze data including FId0-3 and BW0 classes, time post-weaning, and their interactions as fixed effects while study and pen were random effects and pig was repeated measure over time. In a separate model, the FI before and after change from phase 1 to phase 2 was studied in the 2 × 2 with the diet change day as covariate. Pigs with Hfi showed greater (P &amp;lt; 0.05) daily FI until d 14 than their Lfi counterparts (Figure 1). Thereafter, LfiHbw pigs showed a greater FI to an intermediate level with HfiHbw being greatest and LfiLbw least (P &amp;lt; 0.001). Between d 20-28, LfiLbw pigs had the least FI among groups (P &amp;lt; 0.001). From d 28 onward, HfiHbw showed greater daily FI than the other groups (P &amp;lt; 0.05) with LfiLbw often having the lowest FI (P &amp;lt; 0.05) or similar to HfiLbw and LfiHbw (P &amp;gt;0.05). The BW0 was similar between FId0-3 classes (P &amp;gt;0.05), i.e., 8.26, 8.26, 6.85 and 6.77 kg BW for HfiHbw, LfiHbw, HfiLbw and LfiLbw, respectively whereas final BW were all different (i.e., 23.9, 21.8, 20.8 and 18.4 kg BW, respectively; P &amp;lt; 0.001). In absolute figures, all groups had 10 g similar decrease of FI the day of feed phase change followed with 8 g increase the day after (P &amp;gt; 0.05). Time spent eating per feeder visit, steadily increased from d0 (14 min) to d5 (170 min), being greater for Hfi than Lfi (P &amp;lt; 0.05). From d 6 onward, it remained ~172 min/visit showing some tendencies (P &amp;lt; 0.10) for HfiHbw spending less time. In conclusion, the present study pointed out the relevance of weaning BW and initial post-weaning FI as independent factors influencing both daily feed intake behavior and growth performance for the nursery phase.

286 Impact of feeding strategies on bodyweight and body condition in mature AI boars

Abstract The objective of this experiment was to determine how varying feeding strategies for boars impacts body weight (BW), backfat depth, loin muscle depth, Knauer caliper measurements, flank to flank tape measurement, body condition score (BCS), and scrotal width and length. This experiment was conducted over two 9-wk periods. Boars were weighed and measurements were taken every 3 wk during the study. Boars (n = 28; Acuity and Topig Norvsin) from two age groups (9 and 15 mo) and two genetic lines (maternal and terminal) were used during this experiment. Boars were blocked by breed and age and randomly allocated to receive one of the three feed intake (FI) levels of a corn-soybean meal-based diet (met NRC 2012 nutrient requirements) using the NRC (2012) maintenance equation [ME for maintenance = (100*kg BW0.75) + 15 kcal for sperm production]. Treatments were: HIGH (150% of maintenance, n = 9), MAIN (100% of maintenance, n = 10), LOW (80% of maintenance, n = 9) for the first 9-wk period. During the second 9-wk period remaining HIGH and LOW boars were crossed-over to opposite treatments (HIGH-LOW, n = 9; LOW-HIGH, n = 7) and maintenance remained unchanged (MAIN-MAIN, n = 8). Data were analyzed using PROC MIXED in SAS 9.4. Boar was the experimental unit with main effects of feed intake and age, and week serving as a repeated measure. Significance was determined at P &amp;lt; 0.05 and a trend at 0.05 &amp;lt; P ≤ 0.10. Three-way interactions of FI*Age*Week were observed during the first 9-wk period. Young boars fed HIGH had a greater increase in BW (P = 0.002), caliper (P = 0.011), backfat depth (P = 0.003), BCS (P = 0.003), and scrotal width (P = 0.004) than old boars fed HIGH and young boars fed LOW had a greater reduction in these variables then old LOW boars. Boars fed LOW for the first 9-wk period had reduced scrotal length (P = 0.004), greater reduction in BW change (P &amp;lt; 0.001), and reduced tape change (P = 0.021) compared with HIGH and MAIN fed boars. Two-way interactions for the second 9-wk period were observed. HIGH-LOW fed boars had decreased BW (FI*Week; P &amp;lt; 0.001), tape (FI*Week; P = 0.019), caliper (FI*Week; P = 0.012), BCS (FI*Week; P &amp;lt; 0.001), and scrotal width (FI*Week; P = 0.047) while LOW-HIGH boars had increased measurements for these variables over time. Additional two-way interactions during the second 9-wk period included Tape (FI*Age; P = 0.046) and BCS (FI*Age; P = 0.028). Overall young boars had more adverse reactions to the varying feeding strategies than old boars, this included larger changes in BW and composition measures. Young and old boars fed MAIN level lost BW and condition indicating the equation for maintenance energy requirement is not accurate for modern genetics working boars. Future research is needed with varying ages and feed intakes in the boar stud to better understand the impacts of growth, development, and maintenance energy for the modern AI boar.

287 The effect of cooling pad and Moringa oleifera on lactating sows under heat stress

Abstract Lactating sows and their litters are particularly vulnerable to heat stress (HS). HS decreases sow fertility, feed intake, milk production, and litter growth. Approaches are needed to mitigate the negative effects of HS on animal welfare and reduce oxidative damage to tissues associated with HS. Recently, electronic cooling pad (ECP) were designed to remove heat through conductive cooling. The objective of this study was to test the efficacy of ECP and feeding an antioxidant, Moringa oleifera (4% of the diet, M), to sows from late gestation to weaning on their welfare and production performance. A study was conducted using a 2 by 2 factorial arrangements of treatments with mixed parity Yorkshire x Landrace sows (n = 48) mated to Duroc sires. The sows were exposed to moderate HS conditions from gestation d 100 to d 21 of lactation (weaning). To achieve moderate HS analogous to a summer day, farrowing room temperature was increased incrementally from 800 to 1100 h to 32º C and slowly decreased to 26 ºC from 1700 to 2000 h. Sows were limit-fed their specific diets during gestation (1.36 kg 2X/d) and fed for ad-libitum feed intake post farrowing. Treatments included HS+control corn-soy meal diet (CS), HS+M, ECP+CS, ECP+M (n = 12/treatment). Sow RR and RT were measured four times daily (0600, 1300, 1600, 1900 h) and sow feed intake during lactation was measured along with body weight (BW) change from farrowing to weaning. Birth litter size was determined, and growth of standardized litters (n = 13 piglets/sow) was measured. Milk was collected during active farrowing (d 0) and on d 3 and d 14 post-farrowing and analyzed for macronutrient content. The use of ECP decreased lactating sow RR (Lsmeans HS = 66.5 bpm, ECP = 28.2 bpm, P ≤ 0.0001), RT (Lsmeans HS = 39.2 ºC, ECP = 38.8 ºC, P = 0.003), and lactation BW loss (Lsmeans HS = -21.67, ECP = -5.1 kg P = 0.002). ECP by time-of-day interactions (P &amp;lt; 0.01) existed for RR and RT with ECP having a greater impact from 1300 to 1900 h than at 0600 h. ECP increased lactation feed intake (P &amp;lt; 0.02). An ECP by diet interaction (P = 0.0004) indicated ECP increased lactation feed intake for the sows fed the CS diet (6.48 kg/d vs 4.42 kg/d, P = 0.0004) but did not affect feed intake of sows fed the M diet. Treatment did not affect litter weaning weight (P = 0.14). M increased percent fat in milk (Lsmeans M = 12.28, CS = 11.06, P = 0.05) across all days of lactation. The reduction in sow RR and RT combined with increased feed intake and decreased loss of BW during lactation indicate that ECP improved sow wellbeing in the HS environment. Neither cooling nor M affected litter growth, despite increased fat content of milk of M supplemented sows and increased feed intake of ECP-CS sows.

285 Impact of feeding strategies on semen concentration, motility, and morphology of the mature AI boar

Abstract The objective of this experiment was to determine if varying feeding strategies of maintenance requirements of boars impacts semen concentration, motility, morphology, and cortisol of the working boar. This experiment was conducted at Purdue University over two 9-wk periods with 1-wk before each 9-wk period serving as baseline for analysis. Boars (n = 28; Acuity and Topig Norvsin) from two age groups (9 and 15 mo) and two genetics (maternal and terminal) were used. Boars were blocked by breed and age and randomly allocated to receive one of three feed intake levels of a corn-soybean meal-based diet formulated to meet NRC (2012) maintenance requirements: HIGH (150% maintenance, n = 9); MAIN (100% maintenance, n = 10); and LOW (80% maintenance, n = 9) during the first 9-wk period. During the second 9-wk period remaining HIGH and LOW boars were crossed-over to opposite treatments (HIGH-LOW, n = 9; LOW-HIGH, n = 7), and maintenance boars were unchanged (MAIN-MAIN, n = 8). Semen was collected once/wk using the gloved hand method and 3 mL of ejaculate was diluted in 27 mL of extender (Androhep Plus, Minitube). Semen concentration (Nucleocounter SP-100), motility (Computer Assisted Sperm Analysis, CASA, CEROS II), and sperm cell morphology (phase-contrast, bright-field microscopy) were analyzed. Data were analyzed using PROC MIXED in SAS 9.4 with boar as experimental unit with main effects of feed intake and age with phase (3-wk period) as repeated measure. Significance was determined at P &amp;lt; 0.05 and a trend 0.05 &amp;lt; P ≤ 0.10. Three-way interactions for the first 9-wk period of feed intake*age*phase was observed for total sperm (P &amp;lt; 0.10) and total normal sperm (P &amp;lt; 0.05) with old boars fed HIGH treatment increasing sperm production, but old boars fed MAIN and LOW decreasing sperm production while young boars had minimal changes in sperm production regardless of feeding levels in the first 9-wk period. No other interactions or main effects were observed for the first period. During the second 9-wk period two-way interactions were observed for total sperm (FI*Age; P &amp;lt; 0.05) and total normal sperm (FI*Age; P &amp;lt; 0.01) with old LOW-HIGH boars having the highest total sperm and total normal sperm concentrations and young LOW-HIGH boars having the least total sperm and total normal sperm concentrations. HIGH-LOW fed boars had the greatest decrease in semen volume compared with the other treatments (FI*Phase; P &amp;lt; 0.01). Boars fed MAIN had minimal impacts on semen parameters compared with HIGH and LOW feed intake treatments. HIGH and LOW feed intake was observed to impact semen parameters in old boars faster than young boars with neither age being able to return to their baseline semen parameters observed at the start of the trial. Future research is needed with varying ages and feed intakes to better understand how nutritional strategies impact semen quantity and quality in the boar stud.

139 Effect of dietary crude protein concentration and sensory feed additive on nursery pig growth performance

Abstract Maximizing growth performance and feed intake for nursery pig diets is an ongoing challenge in the US swine industry. Using sensory feed additives is one strategy to optimize feed intake and growth rates of pigs. Weanling pigs (n = 416; average age = 19.8 d) were used to test the effects of sensory feed additive (SA; Luctamax Piglet, Lucta, Mahwah, NJ) addition to control (CON) and low crude protein (LCP; decreased 4% CP) nursery diets in a 2 x 2 factorial design (CON, CON+SA, LCP, LCP+SA). Decreased dietary CP was achieved by removing or decreasing fish meal and soy concentrate in phases 1 and 2 and reducing soybean meal in phase 3 and adding synthetic amino acids to maintain amino acid ratios (NRC 2012). Nursery treatments were fed in three phases; phase 1 (PH1, d 0-7, 0.10% SA), phase 2 (PH2, d 7-21, 0.10% SA), and phase 3 (PH3, d 21-36, 0.05% SA). Pigs were blocked by initial body weight (BW), sex, ancestry, and housed at 6 or 7 pigs/pen with 15 pens/treatment. Weekly pig BW and feed intake were used to calculate pen average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F). Data were analyzed using GLM procedure of SAS 9.4. During PH1 pigs receiving the CON diets tended (P = 0.065) to have a greater G:F compared with pigs receiving LCP diets. For the remainder of this study there were consistent interactions between dietary CP and SA. When SA was added to the LCP diet ADFI increased but when SA was added to CON diet ADFI decreased and these changes in feed intake often led to similar dietary interactions in ADG. During PH2, pigs fed CON or LCP+SA diets had greater ADFI (P = 0.032) and tended to have a greater ADG (P = 0.094) but reduced G:F (P = 0.100) compared with pigs fed CON+SA or LCP diets. In PH3, pigs fed CON or LCP+SA diets had a greater ADG (P = 0.027) and ADFI (P = 0.011) compared with CON+SA or LCP diets. Pigs fed LCP diets had greater ADFI (P = 0.001) but reduced G:F (P = 0.0001) than pigs fed CON diets. Overall, pigs fed CON or LCP+SA diets had greater ADFI (P = 0.016) and tended to have a greater ADG (P = 0.059) but reduced G:F (P = 0.067) compared with pigs fed CON+SA or LCP diets. Pigs fed CON diets had a greater G:F (P &amp;lt; 0.001) compared with pigs fed LCP diets, while LCP pigs tended to have a greater ADFI (P = 0.054) compared with CON pigs. Inclusion of SA to LCP diet mitigated the adverse impact of replacing whole dietary proteins with high inclusion of synthetic amino acids. Careful consideration is needed when using sensory feed additives so as not to impede growth performance in diets containing traditionally greater levels of crude protein.

PSII-20 Feeding behavior of pigs fed dietary amino acid levels adjusted according to the circadian rhythm

Abstract Pigs are diurnal animals that present feed intake during daylight hours, with feeding peaks in the early morning and late afternoon. However, it is possible that the concentration of amino acids (AA) in the diet throughout the day changes the meal pattern of the pigs. Therefore, the objective of this study was to evaluate the feeding behavior of growing-finishing pigs subjected to adjustment of the concentration of AA in the diet according to the circadian rhythm. Sixty-eight (body weight = 25 kg ± 2.67) barrows were assigned to four treatments, being a daily feeding program (DP) and three sequential feeding programs (SEQ). In DP, dietary AA concentration was adjusted daily, providing 100% of the standardized ileal digestibility (SID) recommendation for the 24-h period. In SEQ, the daily dietary AA concentration was adjusted every 12 h, providing a low AA concentration from 0000 to 1159 h and a high AA concentration from 1200 to 2359 h. The low and high AA concentrations of the SEQ corresponded to ±20%, ±30% and ±40% of daily AA requirements. The experiment lasted 82 d and was divided into three phases. Meal pattern variables were recorded in real time by precision feeders. The information obtained was grouped into four periods: PE1, from 0000-0600 h; PE2, 0601-12:00 h; PE3, 1201-1800 h; and PE4, 1801-2359 h. From this database, the visits to the feeder (n), meals (n), amount of time feeding (min), feed intake (g), and feed intake rate (g/min) were calculated for each period, within each experimental phase. The analysis of variance was performed considering the effects of feeding programs (FP), periods (PE), and their interaction (FP×PE), considered significant when P &amp;lt; 0.05. There was no interaction between FP and PE (P &amp;gt; 0.05; Table1). The visits to the feeder were greater (P &amp;lt; 0.01) in PE2 and PE3 compared with PE1 in phase one and compared with PE1 and PE4 in phases two and three. The meals, amount of time feeding, and feed intake was greater (P &amp;lt; 0.01) in PE2 and PE3 in all phases. Regarding feed intake rate, an PE effect (P ≤ 0.01) was observed in all phases and there was an effect of FP (P &amp;lt; 0.01) in phases one and three. In phase one, pigs ingested feed faster in PE3 than PE1, and in phase three feed intake rate in PE1 was less than in the other (P &amp;lt; 0.01). During phase one, SEQ40 feed intake rate was lower than SEQ30, while in phase three SEQ40 showed lower feed intake rate compared with SEQ30 and DP. Pigs showed greater feeding activity from 0600 to 1800 h. The AA concentration in the diet adjusted according to the circadian rhythm did not change the meal pattern of the pigs throughout the day. However, a decreased feed intake rate was observed in SEQ40 group in phases one and three.

274 Socialization of piglets during suckling enhanced feed intake after weaning but did not alter their response to dietary amino acid concentration

Abstract The present study hypothesized that pre-weaning socialized piglets would reduce damaging behavior and when fed an increased dietary standardized ileal digestible (SID) Lys (and amino acids) to net energy (NE) ratio post-weaning would increase early post weaning feed intake (FI) and growth performance, and in nursery pigs. Socializing included two groups of five sows and their litters for which farrowing pen walls were removed allowing piglets to co-mingle for 10 d before weaning (S) whereas traditionally housed piglets pertained to housing a single sow with her litter (T; n = 15). At weaning, 120 mixed-gender piglets [7.2 ± 0.7 kg body weight (BW)] were allocated based on litter origin, sow parity, and piglet BW to 12 pens equipped with single-space electronic feeding stations with 10 pigs/pen for a 41-d study. In this 2 × 2 factorial arrangement, factors were litter background (socialized vs. traditional) and dietary SID Lys: NE (High 1.32 vs. Low 1.15 SID Lys:NE MJ/kg). Daily individual FI and BW and skin injuries at different timepoints after weaning were determined. Wheat-barley based diets were isoenergetic (10.6 MJ/kg) and offered in two phases (i.e., d 0-14 and d 14-41). The day after weaning, socializing reduced the proportion of piglets with more than five skin injuries from 45.7% to 3.0% compared with traditional housing (P &amp;lt; 0.05). Early post-weaning, daily FI was 50% greater for S-LowLys:NE pigs than S-HighLys:NE on d1, then, T-LowLys:NE was greatest (~25% above other treatments) during d 3-6 (all P &amp;lt; 0.05). The trend maintained during d 6-8 with T-LowLys:NE and S-HighLys:NE being similar each other (P &amp;gt; 0.05). The average number of visits per day during the first 10 d was greater (P &amp;lt; 0.01) for S-HighLys:NE and T-LowLys:NE (33 visits each) compared with T-HighLys:NE (24 visits). Overall, S-HighLys:NE pigs tended (P &amp;lt; 0.10) to have a greater end BW (23.8 vs. 22.1 kg) and a greater d 0-41 average daily gain (ADG) than T-HighLys:NE (530 vs. 472 g/d). For d22-29, the average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (FE), were greater for S-HighLys:NE and T-LowLys:NE compared with S-LowLys:NE and T-HighLys:NE (P &amp;lt; 0.05). No other meaningful interactions were observed between socializing and Lys:NE on growth performance. However, looking at main factors, socializing increased ADG during d 29-41 by 9% (P = 0.01) coinciding with a 4% greater FE (P = 0.09). The data suggest that traditionally housed piglets fed a HighLys:NE diet post-weaning had lower daily FI and growth performance compared with T-LowLys:NE and socialized piglets irrespective of the Lys:NE contrast. In conclusion, the present study led to a better understanding of nutritional requirements and FI in situations with different pre-weaning housing schemes of piglets. In the present conditions, pre-weaning socialization of pigs may stimulate feed intake earlier post-weaning and allow a better transition independently from the Lys (and amino acid) to NE ratio.

12 Effects of increasing SID lysine (Lys) and metabolizable energy (ME) levels of lactation diets fed to young and multiparous sows

Abstract Providing insufficient lysine to lactating sows can reduce piglet performance and subsequent farrowing performance of sows. Current SID lysine and ME recommendations for lactating sows are approximately 60 g/d and 20 Mcal/d, respectively. Because of variations in feed intake during lactation, a portion of sows do not meet recommended Lys intake levels. There is no clear understanding of the Lys:Calorie ratio when dietary energy is increased in the summer to ensure adequate caloric intake. The objective was to evaluate a potential advantage of feeding diets with SID Lys and energy levels that exceed recommendations to lactating sows. A total of 855 sows were fed during the summer of 2023 in 2×2 factorial arrangement of treatments in a randomized complete block design. Factors included SID lysine [low (0.85%) vs high (1.11%)] and ME [low (3,183 kcal/kg) vs high (3,334 kcal/kg)]. Diets were formulated to deliver 61 g of SID lysine at 0.85% inclusion to sows that consume 7.2 kg of complete feed per day. Primary outcome variables were sow body composition, lactation average daily feed intake (ADFI), average piglet weaning weight, and pre-wean mortality. There were no interactions between treatments (P &amp;gt; 0.05). SID Lys intake was 61.2 and 76.4 g/d for low and high Lys, respectively (P &amp;lt; 0.01). ME intake was 21.9 and 23.4 Mcal/d for low and high energy, respectively (P &amp;lt; 0.01). Contrary to expectations, ADFI did not differ (P = 0.25) between sows fed the low- and high-energy diets, however, sows fed low lysine consumed 0.29 kg more feed (P &amp;lt; 0.01) per day compared with sows fed high lysine. There were no differences (P ≥ 0.70) in the number of piglets born alive for any treatment group. Sows fed high energy had 0.27 fewer (P &amp;lt; 0.01) still-born piglets per litter compared with sows fed low energy. Pre-wean mortality was also reduced (P = 0.05) by 0.76 percentage units in litters of sows fed the high-energy diet compared with litters of sows fed the low energy. Lysine level had no effects on farrowing and litter performance (P &amp;gt; 0.05). Litters from sows fed the high-energy diet gained 1.2 kg more (P = 0.05) body weight during lactation and tended to result in litter-weaned weights that were 1.5 kg heavier (P = 0.06) than litters from sows fed the low-energy diet. Feeding a diet with a greater lysine concentration during lactation reduced feed intake but did not affect litter performance. In contrast, increasing dietary energy immediately before farrowing and during lactation did not affect sow feed intake but reduced pre-wean mortality and resulted in fewer still-born piglets, greater litter gains, and heavier litter weaning weights.