Voluntary Feed Intake Research Articles

Intake and digestibility of four rations with different fiber levels in alpacas (Vicugna pacos).

The aim of this study was to evaluated the impact of different fibre levels in alpaca diet on voluntary feed intake and apparent digestibility, and to estimate the digestibility of organic matter (OMD) from the content of crude protein (CP) in feces. The study was carried out with twelve alpacas (36.7 ± 6.4kg body weight- BW), which were offered 4 treatments with different neutral detergent fiber content (NDF. T1: 40.3%; T2: 62%; T3: 68%; T4: 72%) under a switch back design. Absolute daily dry matter intake (DMI) was higher for T1 (678g/d) than T4 (312g/d) (p ≥ 005). NDF intake was similar between treatments when related to BW or MW (on average 1% BW and 22g/kg MW. p ≥ 0.05). Water intake (L/kg DMI) was higher in T1 compared to the other treatments, with values ranging from 2.9 L/kg DMI(T1) to 2.8 L/kg DMI(T4), respectively (p ≤ 0.05). Digestibility of dry matter, organic matter and CP was higher in T1 than in the other treatments, with average values ranging from 72% for T1 to 32% for T4 (p ≤ 0.05). NDF digestibility was similar among treatments (p ≥ 0.05). The regression equation generated to predict OMD (y) was as follows: y = 0.360 + 0.08294*fecal CP (g/kg OM). Further studies will indicate whether faecal nitrogen can be used to estimate digestibility and hence diet quality in South American camelids.

Socially Acceptable Feed Formulations May Impact the Voluntary Feed Intake and Growth, but Not Robustness of Nile Tilapia (Oreochromis niloticus)

Society is becoming more demanding with aquaculture’s environmental footprint and animal wellbeing. In order to potentially mitigate these concerns, feed formulations could be based on eco-efficient (circular economy-driven) or organic ingredients. This study aimed to investigate the growth performance, feed utilization, and health status of juvenile Nile tilapia (Oreochromis niloticus) when fed with such feeds. The growth trial lasted for 8 weeks, and fish had an initial weight of 31.0 ± 0.5 g (mean ± SD). Fish were fed until visual satiation, in quadruplicate, with one of three isonitrogenous and isoenergetic experimental feeds: a commercial-like feed without fishmeal (PD), a diet based on ingredients compatible with organic certification (ORG), or a feed formulated using circular economy-driven subproducts and emergent ingredients (ECO). Fish fed ECO showed a tendency for decreased feed intake, while ORG fish significantly reduced their intake compared to those fed PD. Consequently, fish fed ECO (62.7 ± 5.4 g) exhibited almost half the growth than those fed PD (107.8 ± 6.1 g), while ORG fish almost did not increase their weight (32.7 ± 1.3 g). ECO and ORG diets had a lower digestibility for protein, lipid, and energy when compared to PD. Feed utilization of fish fed ECO or ORG was also lower than those fed PD. From the health-related genes analyzed, only glutathione reductase (gsr) showed statistically significant differences, being more expressed in fish-fed ECO than those fed PD. Thus, even when such novel formulations induced extreme effects on voluntary feed intake, their impact was noted only in fish growth, but not in robustness.

464 Awardee Talk: Gastrointestinal tract physiology in young pigs

Abstract It is indeed a great privilege to have been awarded the 2024 American Feed Industry Association Award in Nonruminant Nutrition Research. I am honored to follow in the footsteps of many great non-ruminant nutritionists in the industry. I commenced my career in the pork industry with a PhD in digestive nutritional physiology focusing on the newly weaned piglet that, some 35 yr later, is still the subject of significant interest amongst researchers, veterinarians and practitioners, and producers alike. My research was amongst the first to demonstrate direct relationships between voluntary feed intake after weaning and structure and function of the small intestine, corresponding to production consequences. To circumvent intestinal tract disturbances after weaning, antibiotic growth promotors (AGPs)/prophylactic levels of antibiotics and mineral compounds (e.g., ZnO) were routinely included in diets. With the withdrawal of AGPs and in some jurisdictions, in-feed medications and ZnO, the commercial importance of maximizing feed intake in the post-weaning period, with appropriate inclusion of fiber and selected feed additives, has become even more apparent. Some of the more recent work I have been involved in, still involving the gastrointestinal tract, has explored the interrelationships as to why progeny born to first-litter sows perform worse than progeny born to multiparous sows. This is a global issue for the pork industry, especially in view of increasing litter size, yet remains one that has been relatively underexplored. A series of Australian studies using primiparous and multiparous sows, and their progeny conducted on commercial farms confirmed these findings, and reported some significant physiological, immunological, and anatomical differences between piglets born to different parity mothers. Piglets born to first-litter sows are born and weaned lighter than their counterparts born to older sows, suggesting they suffer poorer acquisition of maternal immunity and delays in intestinal tract development and skeletal muscle both in utero and soon after birth, and around weaning. Piglets born to first-litter sows enter weaning with reduced intestinal tract integrity and show some signs of reduced immunocompetence, which taken together, may impede their ability to cope with the stressors of weaning. Weaned piglets are typically treated collectively and are not managed by parity, but lifelong consequences of being born to a first-litter sow suggests further work needs to be done in this field. Gastrointestinal tract structure and function in piglets, and indeed in all neonates, is intricately associated with ‘gut health’, which was a term not even in the lexicon of the pork industry when I began my career. It is pleasing to see that the study of the gastrointestinal tract continues today, stronger than ever, as advances in science and methodologies allow for greater introspection of this organ and its multi-directional influences on the biology of the pig.

Evidence for a constitutive cost of host resistance on body fat growth in ewe lambs from lines selected for resistance or susceptibility to experimental infections with Haemonchus contortus

Although benefits of selection for host resistance to gastro-intestinal nematodes have long been recognized, its costs on production traits remain unclear. A main difficulty when studying those costs is to disentangle genetic effects due to selection from plastic responses induced by infection. Putative costs of host resistance have been extensively investigated in growing sheep. However, while most of those studies have relied on live weight to assess body growth, more comprehensive assessments accounting for body composition are advocated to detect trade-offs. In this study we used 90 female lambs from lines divergently selected on resistance to Haemonchus contortus that we experimentally infected (n = 60) or not (n = 30) under controlled conditions. As those conditions were defined to enable uninfected lambs to fully express their growth potential, we sought to precisely identify the effects of selection for host resistance on health traits and on growth traits. We assessed muscular and fat growth based on repeated measurements with dorsal ultrasonography for all lambs on farm, and with whole-body computed tomography (CT) scans for a subgroup of 18 infected lambs. Lambs achieved a high growth rate, including infected ones despite their high worm burden (confirmed at necropsy in the subgroup). As expected, lambs from the resistant (R) line were less infected than those from the susceptible (S) line. However, the clear pathogenic effects observed on muscular growth and voluntary feed intake were similar between lines. In contrast, a line difference in body fat was supported both by dorsal and volumetric CT measurements. Specifically, lower fat in the R line compared with the S line was observed equally in infected and uninfected groups, thus providing evidence for a constitutive cost of host resistance. Although this cost is not necessarily disadvantageous in nutrient-rich environments exposing animals to excess fat deposition, its consequences in nutrient-scarce environments may be important to promote sustainable breeding strategies for host resistance.

Grazing camels under semi-extensive production system: selectivity, feed intake capacity, digestion and energy expenditure

BackgroundIt was proposed that camels are more effective than other livestock species in selecting plants for their nutritional value. They may self-regulate their voluntary feed intake to satisfy their nutritional needs. This study was designed to investigate camels’ feeding selectivity and ability to cover nutritional requirements when grazing alfalfa (high in protein) and/ or barley (high in energy) in a desert climate.MethodsEighteen lactating camels were equally divided into three feeding treatments. They grazed daily on alfalfa, barley, or a mixed pasture of both, for two periods of one month each. The concentrate supplement was individually administered at 40 g/kg BW0.75, divided into two equal parts, in the morning and in afternoon. Total energy expenditure (EE) was estimated by heart rate (HR) monitors for 48 h after being calibrated by oxygen consumption using an upgraded face mask open-circuit respiratory system.ResultsDuring the first period, camels had a greater forage intake and digestibility when they grazed barley rather than alfalfa, while those grazing mixed pasture performed intermediately. In the second period, camels had a similar forage intake and digestibility among treatments due to a decline in barley intake and digestibility compared to the first period, which was expected since the preferred plant part gradually shifted from barley grains to predominantly straw as a function of time. Similar HR and EE were found across periods and treatments. As a result of greater gross and digestible energy intake in period 1, a better energy balance in period 1 was observed compared to period 2. Camels better utilize barley than alfalfa. Grazing on barley had a higher energy balance than grazing alfalfa alone or in combination with barley. However, camels grazing barley produced lower milk yield and energy than those grazing alfalfa alone or in combination with barley, with no interaction detected between period and treatment.ConclusionsLactating camels are able to self-regulate their voluntary intake to cover their energy requirements when they are grazing barley and/or alfalfa supplemented with a concentrate supplement at 40 g/kg BW0.75. Grazing barley is better utilized by camels than alfalfa. The chemical and physical properties of plant species play an important role in the selectivity of foraging camels. It also impacts their intake and digestibility, which is negatively associated with the proportion of cell wall content consumed.

Nutritional management of hyperlipaemia in a jenny: a brief report

An adult jenny (5-years-old, non-pregnant) was presented to the Veterinary Teaching Hospital (VTH) of the University of Sassari, with a recent history of appetite loss, extreme underweight condition and reluctance to move. On physical inspection, emaciation [body condition score, BCS: 3/9], muscular waste [muscular condition score, MCS: 1/5], loose/running faeces [faecal score, FS: 2/8], and a general state of mild dehydration were found. Blood analyses outlined a general undernourishment condition [circulating albumins, ALB: 17.6 g/L (21.6–31.6 g/L)] with underlying systemic inflammatory profile and moderate increase in circulating enzymes to explore liver function [aspartate amino-transferase, AST: 657 u/L (279–430 u/L); alanine amino-transferase ALT: 60 u/L (5–14 u/L); gamma-glutamyl-transferase, γ-GT: 87 IU/L (14–69 IU/L); total bilirubin close to the upper limit, TB: 0.20 mg/dL(0.07–0.21 mg/dL)]and hyperlipaemia [TG: 8.70 mmol/L (0.60–2.87 mmol/L)], following fat depots mobilisation, with total cholesterol closed to the lower limit of the physiological range. Hyper-phosphataemia was linked to haemolytic anaemia [P:1.81 mmol/L (0.77–1.39 mmol/L) and red blood cells, RBC: 4.14 1012/L (4.40–7.10 1012)] aligned with the TB to the upper limit. On ultrasound abdominal imaging, enlarged and hyper-echogenic liver was observed. Based on the clinical evaluation, a condition of hepatic lipidosis was diagnosed, requiring dedicated nutritional treatment to solve the extreme emaciation along with the metabolic disorder in support of medical therapy. A two-step feeding protocol was planned to support treatments aiming at immediate re-hydration (Ringer lactate solution 2 ml/kg/8 h). The nutritional objectives were meant at first to restart the voluntary feed intake. Gradual increasing energy provision through a palatable hay-based diet was planned to cover one fourth of daily metabolizable energy requirement calculated on the expected metabolic weight, adjusted according to the daily intake of feed and clinical condition. At the conclusion of this first 7-day phase, circulating blood parameters were closer to the reference values and the BCS moved from 3 to 4 out of 9. Bowel motility was restored, and faecal score improved (4/8). In the second phase, allowance to pasture and a combination diet with compound mixed feed were designed. Within four weeks of starting the nutritional plan, blood parameters were re-established to reference values. The gradual feed provision calculated in this two-phase approach proved successful in support of the overall clinical improvement observed after four weeks of treatment, in a severely undernourished jenny with compromised liver functions.

Effect of strategic supplementation of a novel feed supplement on zoo-technical attributes, metabolic profile, production and reproduction performance of buffaloes

The present experiment aimed to establish the efficacy of a novel feed supplement (NFS) on nutrient intake, energy status, metabolic profile, milk yield, reproductive performance and its socio economic impact on problematic post-partum buffaloes under field condition. Twenty four post-partum buffaloes were randomly and equally assigned to CON and NFS groups for 120 days of experimental feeding period. The animals in CON group were fed on basal roughages and concentrate mixture @ 20% of DMI as per the farmers’ practices, whereas, buffaloes in NFS group were fed according to CON with additional novel feed supplement @ 0.25% of BW. The voluntary feed intake and average daily gain in body weight were increased in NFS than CON group. The buffaloes fed NFS diet exhibited higher Hb, haematocrit, serum glucose and lower NEFA. Serum minerals (Ca, iP, Zn, Cu, Fe, Mn), metabolic hormones (T3, T4, GH, IGF-1) and total anti-oxidant capacity were enhanced in NFS group. The milk yield and conception rate were also improved significantly following strategic supplementation of NFS. Analyses of cost benefit of milk yield revelled that the benefit-cost ratio was improved in NFS fed buffaloes. Thus, it can be concluded that strategic supplementation the novel feed supplement @ 0.25% of BW significantly improved the nutrient intake, energy balance, metabolic profile, milk yield and reproduction performance of problematic buffaloes under field condition during early post-partum period.

Protein supplementation during mid-gestation affects maternal voluntary feed intake, performance, digestibility,and uterine blood flow of beef cows.

This study aimed to assess the impact of protein supplementation and its interaction with calf sex (CS) on the performance, metabolismand physiology of pregnant beef cows. Fifty-two multiparous Zebu beef cows carrying female (n = 22) and male (n = 30) fetuses were used. Cows were individually housed from day 100 to 200 of gestation and randomly assigned to restricted (RES, n = 26) or supplemented (SUP, n = 26) groups. The RES cows were ad libitum fed a basal diet (corn silage + sugarcane bagasse + mineral mixture), achieving 5.5% crude protein (CP), while SUP cows received the same basal diet plus a protein supplement (40% CP, at 3.5 g/kg of body weight). All cows were fed the same diet during late gestation. Differences were declared at p < 0.05. No significant interaction between maternal nutrition and calf sex was found for maternal outcomes (p ≥ 0.34). The SUP treatment increased the total dry matter (DM) intake (p ≤ 0.01) by 32% and 19% at mid- and late-gestationrespectively. The total tract digestibility of all diet components was improved by SUP treatment at day 200 of gestation (p ≤ 0.02), as well as the ruminal microbial CP production (p ≤ 0.01). The SUP treatment increased (p ≤ 0.03) the cows'body score condition, ribeye area, the average daily gain (ADG) of pregnant components (PREG; i.e., weight accretion of cows caused by pregnancy)and the ADG of maternal tissues (i.e., weight accretion discounting the gain related to gestation) in the mid-gestation. The SUP cows exhibited a lower maternal ADG (p < 0.01) compared to RES cows in late pregnancy. There was a 24% additional gain (p < 0.01) in the PREG components for SUP cows during late gestation, which in turn improved the calf birthweight (p = 0.05). The uterine arterial resistance and pulsatility indexes (p ≤ 0.01) at mid-gestation were greater for RES cows. In conclusion, protein supplementation during mid-gestation is an effective practice for improving maternal performance, growth of the gravid uterusand the offspring's birth weight.

Responses of nutrient utilization, rumen fermentation and microorganisms to different roughage of dairy buffaloes

Dairy buffaloes are typically fed a high-forage, low-quality diet with high fiber. These conditions result in an inherent energy and protein inefficiency. In order to make full and rational use of feed resources and improve the production level and breeding efficiency of dairy buffaloes, the effects of various roughages on nutrient digestibility, ruminal fermentation parameters, and microorganisms in dairy buffaloes were studied in this experiment. Three ternary hybrid buffaloes, with an average body weight of 365 ± 22.1 kg, were selected and fitted with permanent rumen fistulas. They were fed six different diets, each consisting of 1 kg concentrate supplement and one of six types of roughage, including alfalfa hay (A diet), oat hay (O diet), whole corn silage (W diet), king grass (K diet), sugarcane shoot silage (S diet), and rice straw hay (R diet) according to an incomplete Latin square design of 3 × 6, respectively. The pre-feeding period of each period was 12 d. From day 13 to 15 was the official experimental period. During the prefeeding period, free feed intake for each roughage was determined, and during the experiment, the roughage was fed at 90% of the voluntary feed intake. Digestion and metabolism tests were carried out using the total manure collection method to determine the feed intake and fecal output of each buffalo, and to collect feed and fecal samples for chemical analysis. On day 15, rumen fluid samples were collected two hours after morning feeding to determine rumen fermentation parameters and bacterial 16 S rRNA high-throughput sequencing was performed. The results showed that DM and OM digestibility were greatest for the W diet and lowest for the S diet. The rumen pH of the O diet was significantly greater than that of the W diet. The concentration of rumen fluid NH3-N (mg/dL) increased with increased CP content. The concentration of total volatile fatty acids (mmol/L) in the rumen decreased with increased NDF content but increased with increased NFC content. The relative abundances of Bacteroidetes, Firmicutes, and Spirochaetes were 57.03-74.84%, 14.29-21.86%, and 0.44-1.43% in the different quality roughage groups. Bacteroidetes were mainly Prevotellaceae1 and Rikenellaceae RC_gut_group with relative abundances of 30.17-45.75% and 3.23-7.82%. The relative abundance of Patescibacteria and Spirochaetes decreased with increasing roughage quality. These results provide a theoretical and practical basis for evaluating the nutritional value of dairy buffalo feed, utilizing feed resources, matching rations, feeding scientifically, and protecting animal health.

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.

Growth performance of gilthead sea bream (Sparus aurata) fed a mixture of single cell ingredients for organic diets

The aim of this study was to investigate the growth performance of gilthead sea bream (Sparus aurata) fed with a mixture of a single cell ingredient (SCI) (bacterial protein, yeast protein and algae) for organic aquaculture. Sea bream with an initial mean body weight of 6.87±0.07 g were randomly allocated to 250-litre tanks. Four isonitrogenous, isolipidic and isoenergetic diets were formulated by replacing organic fishmeal trimmings with 0% (control), 12% (SCI12), 15% (SCI15) and 18% (SCI18) of the SCI mixture. Each diet was distributed to the groups in triplicate. The fish were fed three times daily until satiation and the experimental period was 60 days. Survival rates and voluntary feed intake were similar in the fish with the different feed treatments (p > 0.05). Similar (p > 0.05) growth performance (final weight, SGR) and feed conversion ratio (FCR) were observed in fish fed all SCI-based diets, which was superior to the control diet treatment. Apparent protein digestibility was similar among treatments, but lipid digestibility was significantly reduced in the SCI15 and SCI18 groups compared to the SCI12 group. The specific activities of trypsin, total alkaline protease and lipase were increased in fish fed the SCI15 diet (p < 0.05). The protein content in the fillet was significantly increased and the lipid content was decreased in the SCI12 and SCI18 groups compared to the other groups. No adverse effects on liver and intestinal histology were observed in the different groups. The results suggest that organic fishmeal trimmings can be successfully replaced by innovative SCIs based on microbial protein, yeast meal and algae, and that this SCI mixture could be a candidate for organic aqua feed for gilthead sea bream.

Variability in feed intake the first days following weaning impacts gastrointestinal tract development, feeding patterns, and growth performance in nursery pigs.

The present study investigated the effects of voluntary feed intake (FI) the first days after weaning on gastrointestinal development and protein fermentation the first week after weaning and growth performance and feeding patterns during the nursery phase. A total of 144 mixed-sex weaned pigs (24 ± 2 d old; 7.2 ± 0.8kg body weight [BW]) were allocated to 12 pens with 12 pigs/pen. Each pen was equipped with an electronic feeding station for monitoring individual FI during a 40-d study. Pigs were classified based on their cumulative FI over the initial 3 d after weaning (FId1-3) being above or below their pen median FId1-3 (high = 919 ± 244g or low = 507 ± 222g FId1-3). Similarly, weaning BW classes (BW0; high = 7.72 ± 0.59kg or low = 6.62 ± 0.88kg BW) were created to study interactions with FId1-3. Two female pigs with either a high or a low FId1-3 per pen (n = 24) were selected for sampling at d6 and were used to study gastrointestinal development and fermentation products in the small intestine. Feeding patterns per day, FI, and growth performance were measured individually. Low FId1-3 pigs had lower (P < 0.05) daily FI during d0 to d8, d8 to d15, and d22 to d28, BW on d15, d22, d29, and d40, and average daily gain during d0 to d8, d22 to d29, and d29 to d40 compared to high FId1-3. High FId1-3 pigs increased (P < 0.05) the number of visits to the feeder between d1 to d13 and d31 to d35, and the time spent per visit only for d1 to d4 (P < 0.05). The daily rate of FI (g/min) was higher (P < 0.05) for High FId1-3 pigs on d6, d8, d9, and d10, and again several days later (d20 to d39). In addition, the high FId1-3 × high BW0 interaction improved daily FI during d18 to d40 compared to low FId1-3 × low BW0 class (P < 0.05). For the sampling on d6, low FId1-3 pigs had a lighter small intestine, colon, and pancreas, and reduced villi length, smaller villi surface area, and a lower number of goblet cells size in jejunum (P < 0.05), while concentrations of lactic acid, histamine, and cadaverine in small intestinal content were increased (P < 0.05). In conclusion, pigs with high FId1-3 became faster eaters with higher FI and growth rates toward the second half of the nursery, which was similar and additive for pigs with higher weaning BW. High FId1-3 was also associated with greater development of the gastrointestinal tract and a reduced protein fermentation 1-wk after weaning.

Evaluation of Voluntary Feed Intake and Digestibility Organic Feed Ingredients for Adult Female Goats

Limited forage for livestock during the dry season has an impact on low livestock productivity, so a source of feed other than grass is needed as an effort to utilize local resources.The purpose of research is voluntary feed intake level and organik matter digestibility adult female goat given by 3 different feed. It was carried out on experimental farm of Hasanuddin University for 3 months. A total of six a head of adult male goats aged around 1.5 years with preliminary weights 11-15 kg were used and place at individual pen of 100 x 50 x 100 cm with 80 cm above ground level. This research was designed using RBSL with 3 treatments and it was used 2 heads of goat replication. The feed treatment covered 3 kinds of leaves, namely mango (R1), jackfruit (R2), and banana (R3). The voluntary feed intake (kg/day) was measured based on difference between given and remained feed weights. The measurement of feed digestibility (%) using Total Collecting Method, covering total of feed comsumption and total of goat faeces (24 hours) separeted with urine. The research result showed that the voluntary feed intake level R1 leaves was heigher than R2 and R3 leaves, whereas the level of crude fiber digestibility and crude fat of R1 higher than R2 and R3, but digestibility of crude protein R3 higher than R1 dan R2.

29 The Role of Leptin and Its Regulation in the Hypothalamus of Neonatal Calves

Abstract The constant occurrence of increased feed intake in offspring exposed to intrauterine growth restriction has been noted across multiple species including ruminants. In ruminants, reduced circulating leptin concentrations from birth through the first week or two of life may influence the development of the appetite center of the hypothalamus. It should able be noted that increased circulating cortisol at birth has been associated with this decreased circulating leptin in the perinatal ruminants, yet information is limited as to any cause and effect relationship between the two hormones. The objectives of these studies were to test directly the effects of exogenous cortisol on leptin concentrations relative to development of the hypothalamus in perinatal calves and voluntary feed intake as yearling. In two experiments, Holstein bulls (n = 27) and calves (n = 32 males; n = 30 females) from commercial Angus cows were assigned to treatments at parturition (day 0). Calves were intravenously infused with either a low cortisol [LC; n = 9, 3.5 ug/kg of body weight (BW)], high cortisol (HC; n = 9, 7.0 ug/kg BW), or a control (CON; n = 9, saline). Calves were administered a half dose of their respective treatment 24h postpartum. Jugular vein blood samples were collected before infusion and daily until d 17 or necropsy. At 5 days of age Holstein bull calves were euthanized where cerebral-spinal fluid (CSF) and hypothalamic tissue were collected. Serum and CSF leptin concentrations were analyzed via RIA. Neuronal growth factors were analyzed in hypothalamus samples via qRT-PCR. In experiment 2, yearling calves entered a GROWSAFE System and daily feed intake (FI) measured. Animals were allowed a two-week adjustment period to a growing ration for heifers and a finishing ration for steers. Heifer body condition scores (BCS) were collected at the beginning and end of the trial. Heifers underwent the feeding trial for 70 days and steers until they obtained a back fat (BF) thickness of 1.15 cm. Blood samples were analyzed similar to experiment 1. All data were analyzed via repeated measures using appropriate models of SAS (SAS Institute Inc., Cary, NC). Perinatal dairy bull calves had decreased (P &amp;lt; 0.013) serum and CSF leptin concentrations of HC and LC calves compared with CON. Hypothalamic expression of BDNF, FGF1 and FGF2 were decreased (P &amp;lt; 0.006) in HC and LC compared with CON. During the feeding trial: BW gain, BCS change, and number of feed events were increased (P = 0.001) in LC compared with HC and CON heifers. However, LC observed greater daily FI (P = 0.047) and tended to have greater final BW (P = 0.080) compared with HC and CON steers. In summary, these data support that exogenous cortisol administered to perinatal calves affects leptin production and the appetite center of the hypothalamus when administered during the neonatal period.

3 Overview of Poultry Modeling Evolution

Abstract This presentation aims to review advances in mathematical models used in poultry nutrition and production in the past decades and present an overview of the current status. Models have been developed to improve understanding of growth, voluntary feed intake, nutrient utilization, body composition, responses to nutrient supply, environmental changes, and stressors. Growth models for broilers, turkeys, ducks, layers, and breeders are available mainly based on the Gompertz curve, but a few other mathematical functions are also used. A few models can simulate egg production in layers and breeders. The EFG and Avinesp models, tools from feed additive and genetic companies, among others, will be described or mentioned. These models can describe genetic differences and estimate energy, amino acids, calcium, and phosphorus requirements or multiple biological responses to specific nutrient levels. Most models use the concept of ideal protein or balanced protein to describe responses to amino acid levels. However, very few models can describe responses to modifications of one or two specific amino acids. Compartmental models are mainly based on main chemical components such as water, body and feather protein, fat, and ash. Poultry models seldom consider variability due to feeding ingredient quality, fiber, fat, other mineral composition, or variation in nutrient digestibility. However, some models can predict responses to exogenous enzymes. Most applications can predict body weights and yields at a specific age, and some can estimate nitrogen, calcium, and phosphorus excretion. These models can be integrated with feed formulation software, economic data, and optimizers to simulate multiple conditions and estimate biological, economic, and environmental optimums. Poultry enterprise models can describe the whole production system, estimate the optimum combination of resources, aid in planning and scheduling, and determine strategies for growth. Currently, no official recommendations from academic or private groups are based only on models to estimate nutrient levels. Combinations of empirical data and model results are frequently used for nutritional decision-making. A few tools are available for specialized personnel to decide the energy and amino acid levels to use. The application of electronics and telecommunications triggered the fast production of enormous volumes of data from diverse poultry production sectors. This big data avalanche is starting to help modelers to integrate more accurate information and incorporate natural variability. However, integration between current models and significant data results is still under development. Despite increasing international collaboration in modeling, poultry model developments keep great independence and fundamental differences. One critical issue needed for faster development of poultry modeling is to increase education in modeling. The lack of academic programs offering modeling classes related to poultry caused the low current application of models. However, awareness about the benefits of modeling has increased in the past few years, and efforts are under development.

29 Evaluation of Diet Composition on Early Post-Weaned Feed Intake and Intestinal Health

Abstract Weaning is an inevitable early life stressor in commercial production that can cause an immediate reduction in voluntary feed intake and growth during a critical period of gastrointestinal development. Further, the reduction in voluntary feed intake is strongly correlated with the risk of disease during that period. Therefore, our objective was to test the effect of different dietary interventions on early nursery pig feed intake, performance, fecal consistency, and histological parameters. Over 2 repetitions, a total of 90 newly weaned gilts (19-21 d of age, BW 5.62 ± 1.1 kg) were selected, individually penned and randomly assigned to 1 of 5 dietary treatments (n = 18 pigs/treatment) that included: 1) Control diet (CON), 2) CON + 5% sugar beet pulp (BP), 3) CON + 10% high fructose corn syrup (HFCS), 4) CON + 5% soyhulls (SH), or 5) CON + 3,000 ppm Zn and 200 ppm Cu (d 0-7), and 2,000 ppm Zn and 200 ppm Cu (d 8-14; ZC). Each repetition was conducted over a 14-d period consisting of 2 phases (Phase 1: d 0-7, phase 2: d 8-14). Pigs were all sourced from a natural endemic enteric pathogen positive nursery flow and confirmed positive for rotavirus, coccidia and F18 E. coli. Fecal consistency was scored and feed disappearance was recorded daily. On d 0, 7 and 14, pig BW were collected. Weekly feed disappearance and BW were used to calculate ADG, ADFI and feed efficiency (G:F) within phase and overall. On d 14, all pigs were euthanized, and fixed sections of ileum and colon were collected to assess histopathology including incidence of villus atrophy and colitis. Pig was the experimental unit, and performance and histology data were analyzed by dietary treatment. Daily measures of feed intake were analyzed by repeated measures with the fixed effects of diet, day, and their interaction. Starting BW did not differ across dietary treatments (P = 0.845). Over the 14-d test period, HFCS and ZC treatments tended to increase ADG (0.20 and 0.15 kg/d, respectively) compared with CON, BP and SH (0.09, 0.12, and 0.13 kg/d, respectively; P = 0.076). Further, the addition of a sweetener (HFCS) did not improve daily feed intake, while SH reduced daily feed intakes by 32% compared with all other treatments (P &amp;lt; 0.001). Although all pigs had some degree of diarrhea, fecal consistency did not differ between dietary treatments (P = 0.618). Histopathology scoring for intestinal atrophy (ileum) and colitis (colon) were not different (P = 0.645 and 0.440, respectively). In conclusion, the addition of BP, HFCS, SH and ZC had an effect on growth and feed intake but there was no benefit in atrophy, colitis, and fecal scores when encountering a natural enteric pathogen burden.

107 Yeast-Based Postbiotic Supplementation in Sow Diets to Enhance Offspring Growth and Health Through the Nursery Period

Abstract Litter size and the resulting nutritional demand on the sow continue to increase while sow mortality and culling rate are also increasing. Non-nutritive feed additives may enhance sow health and thereby improve offspring growth and productivity after weaning. The objective of this study was to evaluate the impact of yeast-based postbiotic supplementation in gestation and lactation diets on offspring performance through the nursery period. Gestating sows (N = 53; Parity 0 to 5; BW = 242.7 ± 7.1 kg) in 2 breeding groups were blocked by parity and assigned to either a control (CON) diet or a diet supplemented with a yeast-based postbiotic (SUP) at 0.5% in gestation from d 80 to 113 of gestation and 0.2% in lactation (d 114 of gestation to weaning at 20 ± 2 d). Sow reproductive performance and offspring growth from birth to 65 d of age were monitored. At weaning, pigs were allotted to pens within maternal dietary treatment (10 pigs/pen; 31 to 32 pens/maternal treatment; 630 total pigs; BW = 6.18 ± 0.86 kg) and all piglets received common nursery diets in a 4-phase program. Pigs were weighed at week 1, 2, 4, and 6 after weaning. Sow body weight and or reproductive performance (Piglets born alive/litter, 14.4 vs 14.1; piglet birth weight, 1.45 vs 1.48 kg; piglets weaned/litter, 13.0 vs 12.9; lactation sow feed intake, 6.4 vs 6.8 kg/d) was similar in CON and SUP sows, respectively. In the first week after weaning, pigs from SUP sows had greater (P = 0.03) feed intake (0.14 vs 0.13 kg/day) and tended to have decreased (P = 0.06) proportion of pigs that lost body weight (5.6 vs 11.0%). The improved feed intake in the first week after weaning may explain the decreased fallback rate in pigs from SUP sows. Across both sow groups, by 65 d of age, body weight (21.53 vs 21.76 kg), average daily gain (0.36 vs 0.37 kg/day), average daily feed intake (0.54 vs 0.53 kg/day), gain efficiency (0.67 vs 0.69 kg), and mortality (1.26 vs 1.60%) was similar in piglets from CON and SUP sows, respectively. The postbiotic in sow diets positively impacted voluntary feed intake of pigs in the first week after weaning, during a period when feed intake is often low and erratic.

168 Bentley Lecture: Feeding Co-Products to Pigs to Reach Sustainable Food Production and Reduce Feed Cost

Abstract Changes occurred in the last two pandemic years that resulted in tremendous pressures on feedstuff supply. In Canada, causes for reduced cereal, pulse, and oilseed grain supply included a failed crop harvest in Western Canada in 2021 and increased demand for plant protein for food ingredients and for plant oils for cooking and renewable diesel added further pressure. Since January 2022, COVID-associated inflationary pressures, strained supply chains, the Russian invasion of Ukraine, and speculation have increased feedstuff prices further. Grains and tubers may serve as feedstuffs but are also processed into human food, fuel, and bio-industrial products. Together with these products, feed co-products such as distillers dried grains with solubles, canola meal and expeller, wheat millrun and bran, and sugar beet pulp are produced. As omnivores, pigs are ideally suited to convert these non-human edible co-products into high quality animal protein for human consumption. Thereby, co-products can reduce reliance on human edible grains to raise pigs and partially offset increases in feed cost provided their price is less per unit of net energy or digestible lysine, but also present risks, feeding challenges, and opportunities. First, processing of co-products adds variability in macronutrient profile beyond the intrinsic variability of crops. Thus, feed quality evaluation to regularly update digestibility profiles of energy, amino acid, and phosphorus is important. Second, fermentation and heat processing impact amino acid and phosphorus availability. Overheating reduces lysine availability due to Maillard reactions, reduces heat-labile anti-nutritional factors, but combined with fermentation, may increase mineral availability. Third, co-products may possess starch and fiber characteristics that benefit gut health. Fourth, co-products may contain chemical residues and mycotoxins such as deoxynivalenol that survive or are augmented by processing that reduce voluntary feed intake. Fifth, due to their decreased digestibility, dietary inclusion of co-products generally increases excretion of organic matter, P, and N by pigs. Technologies such as tail-end processing and feed enzymes are thus required to increase nutrient digestibility. Finally, dietary inclusion of co-product may impact carcass characteristics and pork quality. For example, inclusion of high fiber co-products reduces dressing percentage and inclusion of high unsaturated fatty acid co-products softens pork fat. In conclusion, the feeding of co-products may reduce feed costs per unit of pork produced, but also provides challenges to achieve cost-effective, predictable growth performance, carcass characteristics, and pork quality. While feeding co-products remains a solution to reduce feed cost, feeding co-products in substitution of grains is now also seen as a piece of the puzzle to reach sustainable food production systems.

Microalgae as functional feed for Atlantic salmon: effects on growth, health, immunity, muscle fatty acid and pigment deposition

Microalgae are increasingly being investigated as functional feed additives in a variety of fish species, but our knowledge on how microalgae supplementation affects Atlantic salmon remains limited. We hypothesized that microalgae inclusion of 8% in the feed would improve performance, fatty acid and pigment deposition as well as health and immunity of Atlantic salmon reared in recirculating aquaculture systems (RAS). We fed Atlantic salmon smolts with five different microalgae enriched diets containing Tetraselmis chuii (TC), Arthrospira platensis (AP), Schizochytrium limacinum (SL) or Chlorella vulgaris, either intact (CVI) or as broken cell wall derivative (CVB) or a control diet (CD). After eight weeks of feeding in brackish water (13 psu), all groups were transferred to seawater (32 psu) for additional two weeks. Our results indicate that CVB improved feed conversion and protein retention, but reduced condition factor (p &amp;lt; 0.05) compared to fish fed with a control diet. Voluntary feed intake decreased in seawater, but was similar among diet groups. The amount of docosahexaenoic acid was particularly high in SL-fed fish and alpha-linolenic acid was enriched in fish fed CVI, CVB and TC (p &amp;lt; 0.05). Following seawater transfer, fat content and monounsaturated fatty acids decreased in the muscle, while polyunsaturated fatty acids increased. Lutein was present in all muscle samples, but highest concentrations were found in CVB-, CVI- and TC-fed fish. In the anterior intestine, microalgae supplementation induced differentially regulated trout protein 1 (drtp1) expression in CVI- and CVB-fed fish, but reduced the expression of interleukin 1 and 10 receptor (il1r2 &amp;amp; il10rb) in CVI-fed fish. In the liver, feeding CVI and SL induced complement C1q like 2 (c1ql2) expression, while reducing serum amyloid A5 (saa5) expression. Superoxide-dismutase protein concentration was induced in the liver of fish fed SL, while myeloperoxidase was reduced in most microalgae-fed groups. In conclusion, we show that commercially relevant microalgae can be used as functional feed additives for Atlantic salmon promoting different health aspects without negatively affecting their growth performance when cultivated in RAS.

Differential voluntary feed intake and whole transcriptome profiling in the hypothalamus of young sheep offered CP and phosphorus-deficient diets.

A reduction in voluntary feed intake is observed in ruminants consuming nutrient-deficient diets, such as those with a low CP or P content, and has been attributed to active metabolic regulation, rather than a physical constraint. The hypothalamus is the key integrator of feed intake regulation in mammals. The objectives of this experiment were to (1) establish a model of metabolic feed intake regulation in ruminants consuming diets of variable CP and P content, and (2) determine key biochemical pathways and influential points of regulation within the hypothalamus. Merino wethers [n=40; 23.7±1.4kg liveweight (mean±SD)] were fed one of five dietary treatments (n=8/treatment) for 63days in individual pens. The treatments included targeted combinations of high (H) and low (L) CP (110 and 55g/kg DM) and high and low P (2.5 and 0.7g/kg DM) with 9MJ metabolisable energy (ME) per kg DM which were fed ad libitum (UMEI; unrestricted ME intake) resulting in four experimental diets (HCP-HP-UMEI, LCP-HP-UMEI, HCP-LP-UMEI and LCP-LP-UMEI). An additional nutritional treatment (HCP-HP-RMEI) restricted intake of the HCP-HP diet to an equivalent ME intake of wethers consuming the LCP-LP-UMEI treatment. Wethers offered the LCP-HP-UMEI, HCP-LP-UMEI and LCP-LP-UMEI treatments consumed 42, 32 and 49% less total DM (P≤0.05), respectively than the HCP-HP-UMEI treatment, and this was not attributable to any physical limitation of the rumen. Plasma concentrations of urea nitrogen and inorganic phosphate indicated that these nutrient deficiencies were successfully established. To assess potential mechanisms, RNA-seq was conducted on samples from the arcuate nucleus (ARC), ventromedial hypothalamus and lateral hypothalamus of the wethers, yielding a total of 301, 8 and 148 differentially expressed genes across all pairwise comparisons, respectively. The expression of NPY, AGRP and CARTPT, known for their regulatory role in mammalian feed intake regulation, had a similar transcriptional response in the ARC of wethers consuming nutrient-deficient treatments and those consuming a ME-restricted treatment, despite these wethers expressing behaviours indicative of satiated and hungry states, respectively. In addition, genes involved with glycolysis (TPI1), the citric acid cycle (CS, OGDH, GLUD1, GOT1) and oxidative phosphorylation (COX5A, ATP5MC1, ATP5F1B, ATP5MC3) were downregulated in the ARC of wethers fed a nutrient deficient (LCP-LP-UMEI) relative to the non-deficient (HCP-HP-UMEI) treatment. In summary, a model for voluntary feed intake restriction was established to determine genome-wide molecular changes in the hypothalamus of young ruminants.