Lower Feed Intake Research Articles

Effects of dietary vitamin E and fat supplementation in growing-finishing swine fed to a heavy slaughter weight of 150 kg: I. Growth performance, lean growth, organ size, carcass characteristics, primal cuts, and pork quality.

The study aimed to assess the effect of vitamin E (VE) supplementation and fat source on growth performance, lean growth, organ size, carcass characteristics, and pork quality of pigs at a heavy slaughter weight of 150kg. A total of 64 pigs (32 barrows and 32 gilts; 28.41±0.83kg) were blocked by sex and body weight, and randomly assigned to one of eight dietary treatments (n = 8 per treatment) in a 4×2 factorial arrangement with main effects of fat source (corn starch [CS; no fat added], 5% tallow [TW], 5% distiller's corn oil [DCO], and 5% coconut oil [CN]) and VE supplementation level (11 and 200ppm). Five-phase diets were formulated to meet requirement estimates of NRC and fed to pigs with each period of 25kg from 25 to 150kg. Increasing dietary VE supplementation from 11 to 200ppm tended to increase average daily gain (ADG) in phase 5 (P = 0.08), and gain to feed ratio (G/F) in phase 4 (P = 0.06) and phase 5 (P = 0.06) resulting in increased G/F in the overall period (P = 0.10). Compared with the pigs fed the CS diet in the overall period, the pigs fed DCO diets had greater ADG (P < 0.05), the pigs fed the TW and CN diets had lower average daily feed intake (P < 0.05), and the pigs fed the fat-added diets had greater G/F (P < 0.05). Belly firmness was greatest in the pigs fed the CN diet and lowest in those fed the DCO diet (P < 0.05). Increasing dietary VE level from 11 to 200ppm increased absolute and relative liver weight, absolute ham yield (P < 0.05), and tended to increase the relative yield of picnic shoulder (P = 0.07) and ham (P = 0.06) and the pigs fed the corn oil diet tended to have greater belly yield (P = 0.08) than the other fat treatments. Increasing dietary VE level increased 45-min pH and ΔpH at slaughter but decreased a* value, chroma (P < 0.10), and belly depth (P < 0.05). However, no effects of VE supplementation and fat source were observed on the other carcass traits and meat quality measurements. In conclusion, increasing dietary VE level from 11 to 200ppm slightly increased growth rate and feed efficiency in the late finishing periods, and the addition of fat increased feed efficiency and backfat thickness, decreased lean content, and altered belly firmness. While there were some effects of VE supplementation and fat source observed on organ weight, primal cuts, carcass traits, and meat quality, there was no strong evidence that VE supplementation and fat source materially affected these measurements except for belly firmness.

133 Ranking Mature Beef Cows for Residual Intake Using an Unprocessed Grass Hay Diet and Its Relationship to Greenhouse Gas Exchange

Abstract The objective of this study was to compare high and low residual feed intake (RFI) beef cows when consuming an unprocessed, grass hay diet (93% DM, 8.73% CP, 2.11 Mcal ME, and 59.25% TDN). Relationships of hay intake to carbon dioxide (CO2) and methane (CH4) production were also evaluated. Thirty-six mature Angus and Angus x Hereford cows were assigned randomly to five pens (n = 6 or 9) and individual feed intakes were collected for 52-d using SmartFeed intake units (C-Lock Inc., Rapid City, SD) at a stocking rate of 3 cows per feeder. An open-circuit, gas-quantification system (GreenFeed, C-Lock Inc., Rapid City, SD) was used to collect CO2 (7611.63±714.09 g) and CH4 (283.64±37.10 g) production for 9 days of collection per pen for a minimum of 20 visits per cow (n = 22 cows, 36.18±14.24 visits). Data collection on cows included (means ± SD) dry matter intake (DMI; 13.86±2.16 kg), metabolic body weight (MBW, 111.65±9.28 kg), average daily gain (ADG, 0.77±0.29 kg), and rib eye area by ultrasound (REA, 46.62±6.34 cm).To calculate RFI (0.03±1.71), a multiple regression model was used to predict DMI (PDMI = ADG + REA + MBW; R2=0.50, P = 0.001). Cows were categorized into three RFI classes: low (n = 7), moderate (n = 6), and high (n = 9). Differences between RFI and RFI class and DMI and RFI class were analyzed using PROC MIXED in SAS (SAS, Cary, NC). Low RFI cows (-1.81 kg) consumed 12.08 kg hay DM daily and high RFI cows (1.59 kg) consumed 15.27 kg hay DM daily (P &amp;lt; 0.001). Correlations between DMI and daily gas exchange were estimated using PROC CORR in SAS (SAS, Cary, NC). Pearson Correlation Coefficients were significant between DMI and CO2 (r=0.58, P = 0.004), and CH4 (r=0.70, P &amp;lt; 0.001) production. Differences in feed intake for high and low RFI rankings were similar to previously reported literature when growing cattle consumed energy-dense diets.

Maternal nutrition altered embryonic MYOD1, MYF5, and MYF6 gene expression in genetically fat and lean lines of chickens.

ObjectiveThe objectives of this study were to evaluate the effects of daily feed intake during the laying period on embryonic myogenic differentiation 1 (MYOD1), myogenic factor 5 (MYF5), and myogenic factor 6 (MYF6) gene expression in genetically fat and lean lines of chickens.MethodsAn experiment in a 2×2 factorial design was conducted with two dietary intake levels (100% and 75% of nutrition recommendation) and two broiler chicken lines (fat and lean). Two lines of hens (n = 384 for each line) at 23th week of age were randomly divided into 4 treatments with 12 replicates of 16 birds. The experiment started at 27th week of age (5% egg rate) and ended at 54th week of age. Hatched eggs from the medium laying period were collected. Real time polymerase chain reaction analysis was used to analyse the MYOD1, MYF5, and MYF6 mRNA levels of E7, E9, E11, E13, and E15 body tissues and E17, E19, and E21 chest and thigh muscle samples.ResultsThe results indicated that there were significant effects of line, dietary intake, and interactions between them on MYOD1, MYF5, and MYF6 gene mRNA expression levels in embryonic tissues. Low daily feed intake did not change the expression trend of MYOD1 mRNA in either line, but changed the peak values, especially in lean line. Low daily feed intake altered the trend in MYF5 mRNA expression level in both lines and apparently delayed its onset. There was no apparent effect of low daily feed intake on the trends of MYF6 mRNA expression levels in either line, but it significantly changed the values on many embryonic days.ConclusionMaternal nutrient restriction affects myogenesis and is manifested in the expression of embryonic MYOD1, MYF5, and MYF6 genes. Long term selection for fat deposition in broiler chickens changes the pattern and intensity of myogenesis.

Effects of Taurine Supplementation on Growth, Feed Utilization, Antioxidant Capacity, and Intestinal Microflora of Largemouth Bass Fed a Low Fish Meal Diet

AbstractThe present study was conducted to examine the effects of taurine supplementation on feed intake, growth, feed utilization, body composition, waste output, hepatic antioxidant enzymes, and intestinal microflora of Largemouth Bass Micropterus salmoides that were fed a low fish meal diet. Three isoproteic (49% crude protein) and isolipidic (9.5% crude lipid) diets were formulated: one diet contained 40% fish meal and served as the control (FM diet), and 60% of the fish meal in the FM diet was replaced by soybean meal either without taurine supplementation (SBM diet) or with 0.5% taurine supplementation (SBM+T diet). Lower feed intake, final body weight, weight gain, condition factor, and hepatosomatic index and a higher feed conversion ratio (FCR) were found in fish that received the SBM diet compared to fish that were fed the FM diet, but no significant difference was found in feed intake, final body weight, weight gain, FCR, condition factor, or hepatosomatic index between fish in the FM and SBM+T diet groups. No significant differences were found in nitrogen retention efficiency, body composition, nitrogen waste, or activities of total antioxidant capacity, superoxide dismutase, and glutathione peroxidase among fish fed the different test diets, and the alpha diversity of intestinal microbiota also did not differ among diet groups. The abundance of Proteobacteria and Firmicutes increased while the abundance of Fusobacteria decreased in the SBM diet group relative to the FM diet group; in contrast, dietary taurine (SBM+T diet) restored the abundance of Proteobacteria to a level similar to that in fish receiving the FM diet. This study suggests that the dietary fish meal level for Largemouth Bass can be reduced from 40% to 16% if soybean meal is used as an alternative protein with 0.5% taurine supplementation.

Effect of pond fertilization on growth performance of pirarucu (Arapaima gigas) during grow-out phase

Fertilization of aquaculture ponds has been pointed out as an efficient practice to improve fish feed conversion and growth performance. In this way, the present study aimed to assess the effect of pond fertilization on the growth performance, body composition, and water quality of juvenile pirarucu Arapaima gigas reared in earthen ponds (600 m²) during the grow-out phase. Two fertilized and two non-fertilized ponds were stocked with 208 juvenile pirarucus (19.9 ± 3.6 g and 15.0 ± 0.9 cm) and reared for 100 days. All four ponds were limed before the study. Ponds were fertilized before fish were stocked and weekly until the end of the experiment, and fish offered feed until apparent satiation. Pirarucu reared in fertilized ponds presented higher final weight (20%) and biomass (19%), further to lower feed intake and feed conversion rate (1.31) than fish reared in non-fertilized ponds (1.61). Pond fertilization did not affect the fish coefficient of variation, which was reduced over the culture cycle. The body composition of fish reared in fertilized ponds presented higher water content, protein, and energy retention rates and lowered crude fat and energy. Fertilized ponds presented lower transparency levels and higher pH from the 50th day of culture, whereas ammonia concentration was higher in the fertilized ponds in the first 25 days. Therefore, pond fertilization is a recommended practice for pirarucu during the grow-out phase.

Biomolecules, Fatty Acids, Meat Quality, and Growth Performance of Slow-Growing Chickens in an Organic Raising System.

Simple SummaryThe increasing demand for nutritionally rich quality products by health-conscious consumers has raised the need to explore alternative farming systems such as organic farming. In this study, we report the efficiency of Korat chickens grown in organic farm conditions. The study demonstrates not only that the slow-growing Korat chicken is suitable for organic farming, but also that the organic raising system improves its growth performance and meat quality. Furthermore, the study unveils a set of biochemical traits using synchrotron radiation-based Fourier transform infrared that show significant differences between the meat quality of chickens raised under conventional and organic raising systems, suggesting their potential use as markers to monitor the meat quality. The findings of this study provide evidence for the potential of organic raising systems for commercial adoption in tropical areas such as Southeast Asia.This study was to determine the effect of the organic raising system (OR) on growth performance, meat quality, and physicochemical properties of slow-growing chickens. Three hundred and sixty (one-day-old) Korat chickens (KRC) were randomly assigned to control (CO) and OR groups. The groups comprised six replicates of thirty chickens each. The chickens were housed in indoor pens (5 birds/m2), wherein those in OR had free access to Ruzi pasture (1 bird/4 m2) from d 21 to d 84 of age. In the CO group, chickens were fed with a mixed feed derived from commercial feedstuffs, while those in the OR group were fed with mixed feed derived from organic feedstuffs. The results revealed a lower feed intake (p < 0.0001) and feed conversion ratio (p = 0.004) in the OR. The OR increased total collagen, protein, shear force, color of skin and meat, and decreased abdominal fat (p < 0.05). The OR improved fatty acid with increased DHA, n-3 PUFA, and decreased the ratio of n-6 to n-3 PUFA in KRC meat (p < 0.05). The synchrotron radiation-based Fourier transform infrared spectroscopy and correlation loading analyses confirmed these results. In conclusion, our results proved that OR could improve growth performance and meat quality and suggested the raising system be adopted commercially. In addition, the observed differences in biochemical molecules could also serve as markers for monitoring meat quality.

Dietary Soluble Non-Starch Polysaccharide Level Influences Performance, Nutrient Utilisation and Disappearance of Non-Starch Polysaccharides in Broiler Chickens.

Simple SummaryNon-starch polysaccharides (NSP) constitute a major part of the dietary fibre component in plant-based feed ingredients, accounting for approximately 10% of the nutrients in a poultry diet. However, NSP are generally not considered during formulation of commercial broiler diets. The functions of dietary NSP in poultry diets, including both the soluble and insoluble fraction, has been extensively researched and discussed. The soluble fraction is of particular interest to poultry nutritionists and producers, as it increases digesta viscosity, affecting nutrient digestion and absorption and thus litter quality. Soluble NSP (sNSP) also provides fuel for beneficial microbiota species. The extent of impact of dietary sNSP level on broiler performance and nutrient utilisation is poorly understood. Consequently, in this study, broilers were fed commercial-type diets with varying sNSP levels, and the effects of the sNSP level on ileal and total tract nutrient digestibility and productive performance were evaluated. The results revealed that even a small variation in dietary sNSP content induces an impact in broilers, particularly in young birds. Thus, sNSP level and composition should be considered during formulation of commercial poultry diets.This study evaluated the effect of dietary soluble non-starch polysaccharides (sNSP) on performance and nutrient utilisation in broilers from d 0 to 35. Cobb 500 broilers (n = 480, 80 birds per treatment) were fed either wheat- or corn-soybean meal-based diets formulated to contain either a high, medium, or low sNSP content, in a 2 × 3 factorial arrangement, fed as Starter (d 0–14) and Grower (d 14–35). Birds fed the low sNSP level presented greater BWG at d 0–14 and lower feed intake at d 14–35 compared to birds fed the medium sNSP level (p < 0.005). At d 14, birds fed the high sNSP level presented greater ileal and total tract starch digestibility and total tract sNSP degradability and insoluble NSP degradability, compared to feeding the low sNSP level. At d 35, total tract DM and metabolisability of gross energy was greater in birds fed the medium sNSP level compared to those fed the high or low sNSP level (p < 0.005). Generally, bird performance and nutrient utilisation was greater in birds fed the corn-based diets compared to the wheat-based diets. These results illustrate that dietary sNSP level and composition influences bird performance and nutrient digestibility.

Limiting factors for milk production in dairy cows: perspectives from physiology and nutrition.

Milk production in dairy cows increases worldwide since many decades. With rising milk yields, however, potential limiting factors are increasingly discussed. Particularly, the availability of glucose and amino acids is crucial to maintain milk production as well as animal health. Limitations arise from feed sources, the rumen and digestive tract, tissue mobilization, intermediary metabolism and transport, and the uptake of circulating nutrients by the lactating mammary gland. The limiting character can change depending on the stage of lactation. Although physiological boundaries are prevalent throughout the gestation-lactation cycle, limitations are aggravated during the early lactation period when high milk production is accompanied by low feed intake and high mobilization of body reserves. The knowledge about physiological constraints may help to improve animal health and make milk production more sustainably. The scope of this review is to address contemporary factors related to production limits in dairy cows from a physiological perspective. Besides acknowledged physiological constraints, selected environmental and management-related factors affecting animal performance and physiology will be discussed. Potential solutions and strategies to overcome or to alleviate these constraints can only be presented briefly. Instead, they are thought to address existing shortcomings and to identify possibilities for optimization. Despite a scientific-based view on physiological limits, we should keep in mind that only healthy animals could use their genetic capacity and produce high amounts of milk.

Genetic selection modulates feeding behavior of group-housed pigs exposed to daily cyclic high ambient temperatures.

This study was conducted to evaluate the effect of genetic selection (Lines A and B; Line A pigs have a greater proportion of Pietrain genes than those from Line B and therefore, selected for improved lean tissue accretion) on the feeding behavior of group-housed pigs exposed to daily cyclic high ambient temperatures. Feeding behavior of 78 barrows housed together in a single room was recorded in real time by five automatic feeders. The feeders registered each visit of each pig (day, hour, min, and second) and the amount of feed requested. Daily cyclic high ambient temperature was induced exposing pigs at 22°C from 18.00 to 10.00 h and 30°C from 10.01 to 17.59 h. From this temperature variation, day-period was divided into: 22°C(06-10h), from 6.00 to 10.00 h; 30°C(10-18h), from 10.01 to 17.59 h; and 22°C(18-06h), from 18.00 to 5.59 h. Meal criteria was estimated based on the probability of animals starting a new feeding event within the next minute since the last visit (Pstart). After defining the meal criteria, the number of meals (n), feed intake rate (g/min), feed intake (g/meal), feeder occupancy (min/meal), and interval between meals (min) of each animal were calculated. Greatest probability of starting to feed was observed at 22°C(06-10h), followed by 30°C(10-18h) and then 22°C(18-06h). Regardless of time period, pigs from line A had greater feed intake rate and lower feed intake, feed occupancy per meal and probability of starting a meal when compared with line B pigs. Only line A pigs had greater feed intake and feeder occupancy per meal at 22°C(18-06h) than remainder of the day. This indicates that pig feeding pattern is strongly related to the circadian rhythm. However, the genetic selection for improved lean tissue accretion may modulate pigs feeding behavior under daily cyclic high ambient temperatures.

Feeding guanidinoacetic acid to broiler chickens can compensate for low dietary metabolisable energy formulation

ABSTRACT 1. This study compared the responses of broilers to diets supplemented with the same level of guanidinoacetic acid (GAA) but formulated to have different N-corrected apparent metabolisable energy (AMEn) contents. The study involved 1280, one-day-old Ross 308 broilers, in 64 pens comprising 32 pens of males and 32 pens females, (20 birds in each) aged from 0 to 42 d. 2. Commercial AME levels of 12.55 MJ/kg, 12.97 MJ/kg and 13.18 MJ/kg in the starter, grower and finisher diets, respectively, were set for the positive control (PC) feed. Four dietary treatments were prepared: PC (as above); negative control 1 (NC; PC – 0.21 MJ ME /kg); NC1 + 0.06% GAA; NC2 (PC – 0.42 MJ ME/kg + 0.06% GAA). Each diet was provided in 16 pens (eight male and eight female), following randomisation. 3. Overall, birds fed NC1 had lower feed intakes (FI) compared to birds fed the PC and NC2+ GAA, lower weight gain (WG) compared to all the other diets and lower final body weight than birds fed the GAA diets (P < 0.05). There was a diet x sex interaction (P = 0.039), whereby feeding NC+GAA to female birds improved feed efficiency compared to being fed NC2 and NC1+ GAA, but not in males. Birds fed diets with GAA had a higher poultry efficiency factor (P < 0.001) than those fed NC1. 4. There were no effects of treatment or sex on litter moisture, footpad score, white striping, wooden breast, AMEn, dry matter and fat retention (P > 0.05). However, the diet NC1+ GAA had 11.2% higher nitrogen retention coefficient compared to the NC1 diet (P = 0.038). 5. Overall, the results implied that lower performance induced by a reduction of dietary AMEn in the range of 0.21 to 0.42 MJ/kg was more than compensated by supplementing 600 g/t GAA to the feed.

Plasticity of feeding behaviour traits in response to production environment (temperate vs. tropical) in group-housed growing pigs

Heat stress affects pig metabolism, health and welfare, resulting in reduced growth and important economic losses. The present experiment aimed to evaluate the effects of two climatic environments [temperate (TEMP) vs. tropical humid (TROP)] on feeding behaviour in growing pigs. The feeding behaviour traits were measured with automated feeders and included: daily feed intake, daily eating time, feeding rate, daily number of meals, feed intake per meal, and feeding time per meal. Pigs came from a backcross population between Large White (LW, heat sensitive) and Creole (CR, heat tolerant) pigs. The same 10 F1 LW × CR boars (sire families [SF]) were mated with related LW sows in each environment. Feeding behaviour was recorded for a total of 1,296 pigs (n = 634 pigs for TEMP and n = 662 pigs for TROP) between 11 and 23 weeks of age. Growth performance and thermoregulatory responses (rectal and skin temperatures) were also measured. Results show that TROP conditions affect feeding behaviour traits: animals had more meals per day but these meals were smaller both in duration and in size, resulting in lower daily feed intake and less time eating per day. Significant SF by environment (GxE) interactions were found for all feeding behaviour traits. When SF were distributed into robust and sensitive groups (previously defined according to performance and thermoregulatory traits), results showed group by environment interactions for all feeding traits, except meal frequency. Moreover, a significant difference in feeding rate between robust and sensitive group was detected in TEMP, suggesting that feeding rate may be a good candidate to evaluate heat tolerance.

Proteomic investigation of brain, liver and intestine in high feed intake and low feed intake Chinook salmon (Oncorhynchus tshawytscha)

In groups of fish, there is often interindividual and intraindividual variation in feed intake. To better understand mechanisms that underpin feed intake, the proteomic profiles of brain, liver, and intestine in high feed intake (HFI) and low feed intake (LFI) Chinook salmon (Oncorhynchus tshawytscha) were investigated. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to quantify 2520 liver, 2783 intestine, and 4052 brain proteins in twenty-seven fish (12 HFI and 15 LFI individuals). Using a population of fish held in tanks, feed intake groups were selected from individual feed intake (%body weight/day (%BW/day)) measured in the meal prior to sampling (HFI: 1.01%BW/day, LFI: 0.41%BW/day). Growth rate and feed conversion ratio were not significantly different between HFI and LFI fish. Protein synthesis in both the intestine and liver of HFI was enriched, indicating increased cellular production in these tissues. In HFI fish, lipid metabolism was the most enriched pathway in the brain. Share of the meal (SM%), calculated as the share of the total feed supplied to the tank, was significantly higher in the HFI (1.59 ± 0.25%) than the LFI (0.72 ± 0.06%) group. This distribution of SM% may suggest that individuals in the HFI and LFI groups were dominant or subordinate, respectively. The LFI group may have suffered from internal or external stressors and accordingly, proteolysis and stress response were activated. This is the first study comparing individual fish with different measured feed intakes at the proteomic level and the outputs provide a preliminary insight into the fundamental molecular landscape of feed intake in Chinook salmon.

Adição de uma mistura de enzimas exógenas a dietas de frangos de corte: impactos no desempenho e custos de produção

ABSTRACT Broiler diets are based on corn, soybean and wheat production; however, some protein ingredients have many antinutritional factors and low digestibility. The objective of this study was to add a blend of exogenous enzymes to the feed with low nutritional value for broilers to reduce production costs and improve digestibility while maintaining good zootechnical performance. The experimental design was completely randomized, including three treatments with five replications (n=15) each: a) positive control (PC), diet calculated for males with average performance; b) negative control + exogenous enzymes (NC+EE), minimum nutrient diet according to the requirements of the production phase, and the enzymatic blend was added; and c) negative control (NC), minimum levels of nutrients for each phase. At 21 days, the PC group showed greater weight gain and lower feed conversion than the NC (P&lt;0.05). At 42 days, PC had lower feed intake than NC (P=0.040), while lower feed conversion was observed in groups PC and NC+EE than NC (P=0.001). The production efficiency index was higher in the PC treatment, but the NC+EE treatment was higher than the NC (P=0.001). Considering production costs and body weight, we found that NC+EE birds had greater profitability. Therefore, we conclude that the blend of exogenous enzymes added to a diet with minimal nutritional levels has practical application in the broiler production system.

TRB3 Deletion Has a Limited Effect on Milk Fat Synthesis and Milk Fat Depression in C57BL/6N Mice

ABSTRACTBackgroundRegulation of the endoplasmic reticulum (ER) stress pathway is critical to mammary epithelial cell function throughout pregnancy, lactation, and involution. Treatment with trans-10, cis-12 conjugated linoleic acid (t10c12CLA) suppresses mammary lipogenesis and stimulates the ER stress pathway. The ER stress pathway includes tribbles pseudokinase 3 (TRB3), a protein that regulates cellular energy and insulin signaling.ObjectivesOur objective was to describe the effect of TRB3 deficiency on milk fat synthesis and determine if TRB3 deficiency protects against suppression of mammary lipogenesis.MethodsFirst, mammary Trb3 expression was observed throughout pregnancy and lactation using ancillary microarray data (n = 4/time point). Second, intake, litter growth, and milk clot fatty acid (FA) profile of Trb3 knockout (KO) C57BL/6N mice were compared with wild-type (WT) and heterozygous (HET) mice throughout first (n ≥ 8/group) and second (n ≥ 6/group) lactation. Lastly, the interaction between Trb3 genotype and 2 treatments that suppress mammary lipogenesis, t10c12CLA and high safflower oil (HO) diet, was investigated in a 2 × 2 factorial design (n ≥ 6/group).Results Trb3 expression was higher during late pregnancy and lactation. Trb3 KO and HET mice had lower feed intake, dam weight, and litter growth throughout first, but not second, lactation than WT mice. Treatment with t10c12CLA decreased litter growth (28%; P < 0.0001) and feed intake (8%; P < 0.0001) regardless of Trb3 genotype. When fed the HO diet, Trb3 KO mice had 17% higher mammary de novo synthesized FAs (<16 carbons; Pint = 0.002) than WT mice. Mammary ER stress and lipogenic genes were mostly unaltered by Trb3 deficiency.ConclusionsOverall, TRB3 plays a minor role in regulating mammary lipogenesis, because Trb3 deficiency had only a limited protective effect against diet-induced suppression of lipogenesis.

NUTRITION AND REPRODUCTION IN SHEEP

High nutrition, but not overfeeding, has a positive effect on ewe reproductive capability in terms of the number of estrous cycles, length of the breeding season, greater ovulation rate, and improved lambing %. Copper deficiency hurts lambing percentage and lamb health. Manganese is required for the ovarian activity to be maintained. Protein is necessary for sheep for optimum sperm capacitation, conception rate, pregnancy, and reduced abortions. Protein insufficiency causes lower feed intake, poorer feed utilization, lower growth rate, lower milk output, and lower wool production. A possible reason for the decline in adult reproductive function is nutritionally impaired ovarian development. Functional impairment in any component of the hormone complex has a direct impact on reproduction. Factors such as photoperiod, nutrition, and social sexual cues, genetics, affect the reproductive capacity of both male and female sheep. In mammals, reproduction is energetically more demanding for the females than for the males.

High Doses of Phytase Alleviate the Negative Effects of Calcium and Phosphorus Imbalance on Growth Performance and Bone Mineralization in Broiler Chickens

This study investigated the effect of calcium (Ca) and phytase interaction on growth performance and bone quality in 1-42-day-old broiler chickens. A total of 624 female one-day-old Ross 308 broilers were allotted to 13 treatments with four replicates and 12 birds per replicate. A 2 × 6 factorial experiment was designed to test the combinations of 0.50% and 1.00% Ca with 0, 500, 1,000, 2,500, 5,000, and 10,000 FTU/kg phytase in the basal diet (0.25% non-phytate phosphorus, NPP). The control diet contained adequate Ca and phosphorus (P). Dietary Ca, phytase, and their interaction affected growth performance and bone mineralization of broilers at 1-42 days of age (p<0.05). The broilers fed with 1.00% Ca had lower body weight gain (BWG) and feed intake (FI) compared with the birds fed with 0.50% Ca (p<0.05). The BWG, FI, leg bone weight, and ash weight of the broilers fed with 0.25% NPP were lower than those of birds fed with the control diet (p<0.05). The addition of 500-10,000 FTU/kg phytase improved growth rate and leg bone quality, especially at 1.00% Ca (p<0.05). No differences were observed in growth performance and bone quality of 42-day-old broilers fed with 1.00% Ca + 2,500-10,000 FTU/kg phytase and the control diet (p>0.05). These data indicated that high doses of phytase (2,500-10,000 FTU/kg) alleviate the negative effects of Ca and P imbalance (Ca-to-NPP ratio = 4.0) on growth performance and bone mineralization of broiler chickens.

Redução temporária de lisina digestível em dietas de leitões em fase de creche: desempenho e viabilidade econômica

ABSTRACT To evaluate the effects of temporary dietary lysine restriction on nursery pigs’ growth performance and its economic viability compared to control diets, 144 piglets (21-d-old) were assigned to randomized blocks, with two treatments and twelve replicates. The treatments were control-lys: lysine level as recommended from 21-32 and 32-42 days and low-lys: 90% of the lysine level of the control-lys diets. From 42 to 62 days, all animals received a control diet. From 21 to 32 days, pigs fed low-lys had worse average daily gain (ADG), feed conversion, and 32-d body weight (BW; P ≤ 0.05). From 32 to 42 days, pigs fed low-lys had lower average daily feed intake, ADG, and 42-d BW (P ≤ 0.05). From 42 to 62 days, pigs had similar performance (P &gt; 0.05). Overall (21 to 62 days), pigs fed the low-lys had lower (P &lt;0.05) ADG and final BW. At 27 and 29 days, pigs fed the low-lys diet had a higher (P≤0.05) incidence of diarrhea. The lowest feed cost and the highest economic efficiency index were recorded for the low-lys treatment. However, pigs fed the control-lys presented a 3.9% higher profitability. In conclusion, a temporary reduction of lysine in the diets of nursery pigs followed by an unrestricted diet in the subsequent period led to worse growth performance and lower economic viability.

Effect of In Ovo Ascorbic Acid Injection and Thermal Manipulation During Incubation on Intestine Morphology of Broilers Reared under Cold and Heat Stress

It was investigated if pre-incubation ascorbic acid (AA) injection in fertile eggs incubated at high temperature impacts the performance, the yield of carcass and parts, and the intestine morphology of broilers reared under heat stress. Three thousand Cobb® fertile broiler eggs were randomly distributed according to weight into three incubations treatments (eggs not injected with AA and incubated at 37.5°C; eggs not injected with AA and incubated at 39°C; and eggs injected with 6 µg AA/100 µL water prior to incubation and incubated at 39ºC). The hatched birds were reared at thermoneutral, cold, and hot house temperatures. Broilers reared under hot temperature presented lower feed intake and weight gain than the broilers of the different rearing temperatures. Egg incubation at 39.0 ºC and 39.0 ºC + AA reduced broiler viability. Carcass and cut yields were not influenced by incubation and rearing procedures. Duodenal goblet cell count was lower in broilers from eggs of the treatment 39ºC + AA than in broilers from the other incubation treatments and in broiler rearing in hot temperature. In the jejunum, the goblet cell counts were higher in broilers that were reared under hot than thermoneutral temperatures. The incubation treatment of 39 ºC+AA increased the goblet cell counts in the ileum of broilers reared under cold temperatures. Rearing temperature influenced the duodenal villi counts, which were lower under cold rearing conditions than in the two other rearing temperatures. The results showed that egg incubation at 39°C, independently of ascorbic acid injection, did not produce an effective epigenetic heat adaptation in broilers.

Effects of feeds, supplemented with humic substances and calcium carbonate, on performance, egg quality and heart rate variability in laying hens.

This study aimed to determine the effects of in-feed inclusion of humic substances (HS) and/or calcium carbonate (CaCO3) on the performance and welfare of laying hens. A total number of 144 Hy-Line Brown laying hens (55 weeks old) were randomly assigned to four treatments, T1-T4 (36 birds per treatment). T1 hens were fed on a control diet without HS or CaCO3, T2 hens were fed on the control diet + 2.00 g per bird per day CaCO3, T3 hens were fed on the control diet + 0.20% HS and T4 hens were fed on the control diet + 0.20% HS + 2.00 g/bird/day CaCO3. The experiment started after 15 days of adaptation and lasted 8 weeks. The parameters evaluated were percentage of hen-day egg production, food consumption, mortality, egg quality parameters and heart rate variability (welfare indicator). Hens in the T3 group showed a significantly lower feed intake than those in the other three groups, however, significantly higher daily egg production was recorded in groups T3 and T4 compared to T1 and T2. Eggshell quality characteristics were significantly improved by HS supplementation and eggs laid by hens in groups T1, and T4 presented paler yolk and shell color than those in the other groups. In conclusion, these results indicated that in-feed inclusion of HS had a beneficial effect on laying hens' productive performance including egg production and eggshells quality.

Impact of relative humidity on the laying performance, egg quality, and physiological stress responses of laying hens exposed to high ambient temperature.

The present study investigated the effects of relative humidity (RH) on the laying performance, egg quality, and stress indicators of laying hens raised at high ambient temperatures. A total of 180 Hy-Line Brown laying hens (68-wk-old) were randomly allotted to one of the following three RH conditions for 12h a day (9:00 a.m.-9:00 p.m.) over four weeks: low RH (LRH; 25% RH), moderate RH (MRH; 50% RH), and high RH (HRH; 75% RH); ambient temperature was 30°C under all treatments. None of the RH treatments affected hen-day egg production, egg weight, or egg mass (P>0.05). However, feed intake was lower in the HRH group than in the LRH group (P<0.05). Plasma corticosterone (CORT) concentration on day 21, yolk CORT concentration on day 3, and albumen CORT concentration on day 7 following RH exposure were higher in the HRH group than in the LRH group (P<0.05). Moreover, plasma HDL-cholesterol concentration on day 14 was higher in the HRH group than in the LRH group (P<0.05). On days 3 and 14, the Haugh unit decreased (P<0.05) in the LRH group compared with that in the MRH and HRH groups. The HRH-exposed laying hens showed the lowest (P<0.05) eggshell thickness on day 14. The absolute weights of eggshell, yolk, and albumen decreased in the HRH group compared with those in the MRH and LRH groups. Overall, high RH lowered feed intake and egg quality except for the Haugh unit, and induced stress response as manifested by elevated plasma, yolk, and albumen CORT concentrations. To our best knowledge, the present study is the first to demonstrate the role of RH in triggering temperature stress responses in laying hens.