Effects of three major protein sources on performance, gut morphology and fermentation characteristics in broilers

1. This study determined the effects of three protein sources (PS), each at two digestibility crude protein (DCP) levels, on performance, gut morphology and fermentation characteristics in the hindgut of broilers.2. It was hypothesised that broilers fed ingredients high in indigestible CP, i.e. rapeseed meal (RSM) or maize gluten (MG), could potentially cause reduced growth, impaired gut health, and more protein fermentation products in caecal digesta. Increasing the DCP level in each of the indigestible CP diets may compensate for these detrimental effects.3. In total, 288 one-d-old male Ross 308 broilers were used in a completely randomised 3 × 2 factorial design, with six replicate pens per treatment. Three PS: soybean meal (SBM), rapeseed meal (RSM) or maize gluten (MG), and two DCP levels: 15.8 and 17.2% were used.4. Broilers fed SBM had increased feed intake and BWG and improved FCR compared with those fed RSM and MG diets. Broilers fed high DCP had better performance compared with those on low DCP. No significant effects of PS or DCP level were found on gastrointestinal tract development, caecal ammonia or volatile fatty acid concentrations.5. Broilers fed SBM had longer villi, smaller crypts and increased villus height to crypt depth ratio compared with those fed RSM and MG diets. Broilers fed RSM diet had a lower caecal pH, and had 16.5% and 14.9% more branched chain fatty acid contents in caecal digesta compared with those fed SBM and MG diets, respectively, indicating more proteolytic fermentation.6. Replacing SBM by RSM and MG negatively affected growth performance and gut morphology. Hindgut protein fermentation was substantially increased in RSM fed birds.7. To a certain extent, retarded growth performance in RSM and MG fed birds could be counterbalanced by increasing the dietary level of digestible CP.

Inclusion of sainfoin (Onobrychis viciifolia) silage in dairy cow rations affects nutrient digestibility, nitrogen utilization, energy balance, and methane emissions

Sainfoin (Onobrychis viciifolia) is a tanniniferous legume forage that has potential nutritional and health benefits preventing bloating, reducing nematode larval establishment, improving N utilization, and reducing greenhouse gas emissions. However, the use of sainfoin as a fodder crop in dairy cow rations in northwestern Europe is still relatively unknown. The objective of this study was to evaluate the effect of sainfoin silage on nutrient digestibility, animal performance, energy and N utilization, and CH4 production. Six rumen-cannulated, lactating dairy cows with a metabolic body weight (BW(0.75)) of 132.5±3.6kg were randomly assigned to either a control (CON) or a sainfoin (SAIN)-based diet over 2 experimental periods of 25 d each in a crossover design. The CON diet was a mixture of grass silage, corn silage, concentrate, and linseed. In the SAIN diet, 50% of grass silage dry matter (DM) of the CON diet was exchanged for sainfoin silage. The cows were adapted to 95% of ad libitum feed intake for a 21-d period before being housed in climate-controlled respiration chambers for 4 d, during which time feed intake, apparent total-tract digestibility, N and energy balance, and CH4 production was determined. Data were analyzed using a mixed model procedure. Total daily DM, organic matter, and neutral detergent fiber intake did not differ between the 2 diets. The apparent digestibility of DM, organic matter, neutral detergent fiber, and acid detergent fiber were, respectively, 5.7, 4.0, 15.7, and 14.8% lower for the SAIN diet. Methane production per kilogram of DM intake was lowest for the SAIN diet, CH4 production as a percentage of gross energy intake tended to be lower, and milk yield was greater for the SAIN diet. Nitrogen intake, N retention, and energy retained in body protein were greater for the SAIN than for the CON diet. Nitrogen retention as a percentage of N intake tended to be greater for the SAIN diet. These results suggest that inclusion of sainfoin silage in dairy cow rations reduces CH4 per kilogram of DM intake and nutrient digestibility. Moreover, sainfoin silage improves milk production and seems to redirect metabolism toward body protein accretion at the expense of body fat.

Adaptation of faecal microbiota in sows after diet changes and consequences for in vitro fermentation capacity

In vitro gas production studies are routinely used to assess the metabolic capacity of intestinal microbiota to ferment dietary fibre sources. The faecal inocula used during the in vitro gas production procedure are most often obtained from animals adapted to a certain diet. The present study was designed to assess whether 19 days of adaptation to a diet are sufficient for faecal inocula of pigs to reach a stable microbial composition and activity as determined by in vitro gas production. Eighteen multiparous sows were allotted to one of two treatments for three weeks: a diet high in fibre (H) or a diet low in fibre (L). After this 3-week period, the H group was transferred to the low fibre diet (HL-treatment) while the L group was transferred to the diet high in fibre (LH-treatment). Faecal samples were collected from each sow at 1, 4, 7, 10, 13, 16 and 19 days after the diet change and prepared as inoculum used for incubation with three contrasting fermentable substrates: oligofructose, soya pectin and cellulose. In addition, inocula were characterised using a phylogenetic microarray targeting the pig gastrointestinal tract microbiota. Time after diet change had an effect (P<0.05) on total gas production for the medium-fast fermentable substrates; soya pectin and oligofructose. For the more slowly fermentable cellulose, all measured fermentation parameters were consistently higher (P<0.05) for animals in the HL-treatment. Diet changes led to significant changes in relative abundance of specific bacteria, especially for members of the Bacteroidetes and Bacilli, which, respectively, increased or decreased for the LH-treatment, while changes were opposite for the HL-treatment. Changing the diet of sows led to changes in fermentation activity of the faecal microbiota and in composition of the microbiota over time. Adaptation of the microbiota as assessed by gas production occurred faster for LH-animals for fast fermentable substrates compared with HL-animals. Overall, adaptation of the large intestinal microbiota of sows as a result of ingestion of low and high fibre diets seems to take longer than 19 days, especially for the ability to ferment slowly fermentable substrates.

Diet structure, butyric acid, and fermentable carbohydrates influence growth performance, gut morphology, and cecal fermentation characteristics in broilers

An experiment with 288 male (Ross 308) 1-d-old broilers was conducted to test the hypothesis that a coarse diet supplemented with butyric acid (BA) and fermentable carbohydrates (FC) improves performance of broilers with a poorly digestible protein source. The interaction effects of diet structure (fine or coarse), FC supplementation (with or without), and BA supplementation (with or without) in a poorly digestible diet based on rapeseed meal (RSM) were tested in a factorial arrangement of 8 (2×2×2) dietary treatments. The coarseness of the diet affected feed intake (FI) (P<0.001), BW gain (P=0.001), and the feed conversion ratio (FCR) (P=0.001) positively. Broilers fed the coarse diets had, on average, 14% heavier gizzards and 11, 7, 5, and 6% lower relative empty weights of the crop, duodenum, jejunum, and ileum, respectively, compared with those fed the fine diets. Dietary coarseness resulted in, on average, 6% greater ileal protein digestibility, 20% lower gizzard pH, 19% greater villus height, 18% lower crypt depth, and 23% reduced cecal branched chain fatty acids (BCFA) compared with chickens fed the fine diets. Broilers fed BA-supplemented diets had an improved FCR (P=0.004) and decreased crypt depth (P<0.001) compared with those fed diets without BA. Fermentable carbohydrate supplementation did not influence growth performance, gut development, or contents of total BCFA and total biogenic amines in the cecal digesta (P>0.05). Supplementation with FC, however, decreased the cecal concentration of spermine by approximately 31% compared with broilers fed diets without FC (P=0.002). In conclusion, feeding a coarse diet supplemented with BA improved performance of broilers fed a diet containing a poorly digestible protein source. The negative effects of a poorly digestible protein source can thus be partly counterbalanced by coarse grinding and BA supplementation in the diet.

Evaluation of free water and water activity measurements as functional alternatives to total moisture content in broiler excreta and litter samples

Litter moisture contents vary greatly between and within practical poultry barns. The current experiment was designed to measure the effects of 8 different dietary characteristics on litter and excreta moisture content. Additionally, free water content and water activity of the excreta and litter were evaluated as additional quality measures. The dietary treatments consisted of nonstarch polysaccharide content (NSP; corn vs. wheat), particle size of insoluble fiber (coarse vs. finely ground oat hulls), viscosity of a nonfermentable fiber (low- and high-viscosity carboxymethyl cellulose), inclusion of a clay mineral (sepiolite), and inclusion of a laxative electrolyte (MgSO4). The 8 treatments were randomly assigned to cages within blocks, resulting in 12 replicates per treatment with 6 birds per replicate. Limited effects of the dietary treatments were noted on excreta and litter water activity, and indications were observed that this measurement is limited in high-moisture samples. Increasing dietary NSP content by feeding a corn-based diet (low NSP) compared with a wheat-based diet (high NSP) increased water intake, excreta moisture and free water, and litter moisture content. Adding insoluble fibers to the wheat-based diet reduced excreta and litter moisture content, as well as litter water activity. Fine grinding of the oat hulls diminished the effect on litter moisture and water activity. However, excreta moisture and free water content were similar when fed finely or coarsely ground oat hulls. The effects of changing viscosity and adding a clay mineral or laxative deviated from results observed in previous studies. Findings of the current experiment indicate a potential for excreta free water measurement as an additional parameter to assess excreta quality besides total moisture. The exact implication of this parameter warrants further investigation.

Ileal microbiota composition of broilers fed various commercial diet compositions

Microbiota plays a role in the release and absorption of nutrients from feed components, thereby affecting digesta composition and moisture content of the excreta. The objective of the current study was to determine the effects of 5 different diets varying in ingredients (medium-chain fatty acids, nonstarch polysaccharides, and starch) on the microbiota composition of ileal digesta of broiler chickens and excreta DM content. Each treatment was repeated 6 times in cages each containing 18 Ross 308 broilers, with growth performance measured from 0 to 34 d of age and excreta DM and ileal microbiota composition analyzed at 34 d of age. Microbiota composition was evaluated using a novel ribosomal RNA microarray technology containing 370 different probes covering various genera, groups of microbial species, and individual species of the chicken gut microbiota, of which 321 had a signal above the background threshold. Replacing part of the animal fat and soybean oil in the wheat-based diet with medium-chain fatty acids (MCFA; 0.3% C10 and 2.7% C12) improved feed efficiency compared with the other dietary treatments. This coincided with a suppression of gram-positive bacteria belonging to the phylum of the Firmicutes, including Lactobacillus species, and species belonging to the family of the Enterococcaceae and Micrococcaceae, whereas the gram-negative bacteria belonging to the family of the Enterobacteriaceae were promoted. None of the other diets used in the present study notably changed the ileal digesta bacteria composition. Excreta DM content was not affected by dietary treatment. The variation between individual birds per dietary treatment was more pronounced than variation caused by feed composition, with the exception of the digesta microbiota of the birds fed the MCFA diet. It is concluded that a diet with MCFA significantly changes the ileal microbiota composition, whereas the effect of the other diets on the composition of the microbiota and excreta DM content is small in broiler chickens.

Peripartal calcium homoeostasis of multiparous dairy cows fed rumen-protected rice bran or a lowered dietary cation/anion balance diet before calving

Milk fever is one of the most important metabolic diseases in dairy cattle. Reducing the dietary cation/anion balance (DCAD) with anionic salts is a common prevention strategy. However, many small European farms cannot use total mixed rations (TMR) in the close-up period. Including anionic salts in compound feeds can result in feed refusals and moderate inclusions to preserve feed palatability results in insufficient DCAD reduction. Rumen-protected rice bran induces the adaptation of Ca metabolism in dairy cows by a reduction of Ca intake and by a reduction of the availability of dietary Ca. In the presence of a negative control, rumen-protected rice bran (2.8 kg/day) was compared with a lowered DCAD diet (from 269 to 4 meq/kg DM) in their effect to prevent milk fever. In a randomized block design, 45 multiparous Holstein cows joined the trial sequentially from 21 days before the expected calving date and were observed until the 8th week of lactation. Feed and nutrient intakes were recorded, and Ca, P, Mg in serum and urine, urine pH, serum NEFA and milk production in early lactation were compared. Feeding rumen-protected rice bran before calving improved the recovery of calcaemia after calving and had a positive effect on DMI after calving. The moderately low DCAD diet did not positively influence serum Ca at calving. Calcaemia recovered even later than in control, and cows showed reduced DMI post-calving and higher NEFA levels in the first 36 h after calving. This moderate reduction of DCAD did not provide an intermediate prevention level indicating that DCAD needs to be reduced to the recommended levels to prevent milk fever. Rumen-protected rice bran may be a suitable feed to reduce hypocalcaemia post-partum and can be included in pre-calving compound feeds representing a palatable alternative to anionic salts.

Predicted high-performing piglets exhibit more and larger skeletal muscle fibers

Postnatal (muscle) growth potential in pigs depends on the total number and hypertrophy of myofibers in skeletal muscle tissue. In a previous study an algorithm was developed to predict piglet BW at the end of the nursery period (10 wk of age) on the basis of BW at birth, at weaning, and at 6 wk of age. The objective of this study was to determine whether the differences in growth performance between poor (PP) and high (HP) performing piglets could be the result of different skeletal muscle properties. Therefore, from a total of 368 piglets (offspring from Hypor sows bred to TOPIGS sires) 2 groups with a divergent growth performance were selected at 6 wk of age: HP (n = 20, predicted BW at 10 wk of age 26.8-30.9 kg) and PP (n = 20, predicted BW at 10 wk of age 16.0-22.9 kg). Piglets were euthanized at 10 wk of age, and samples of the semitendinosus muscle (STN) were collected for histochemistry and gene expression analysis using quantitative PCR (qPCR). At 10 wk of age, realized BW did not differ from predicted BW in either group (P > 0.880). The HP piglets exhibited greater ADG and ADFI from 6 to 10 wk and greater BW at birth and 6 and 10 wk of age (P ≤ 0.002) compared with the PP piglets, whereas G:F ratio was similar (P = 0.417). Superior growth performance of HP piglets was associated with a 1.27-fold higher IGF1 plasma concentration at 10 wk compared with the PP piglets (P = 0.044). The greater weight and muscle cross-sectional area of STN in HP piglets was due to a 1.20-fold increase in total muscle fiber number (TFN; P = 0.009) and 1.34-fold increase in fiber cross-sectional area (FCSA; P = 0.004) compared with the PP piglets. The number of myonuclei per red and intermediate fiber was greater in HP piglets (P ≤ 0.097), but the nucleus-to-cytoplasm ratio was unaffected by the performance group (P = 0.861). The mRNA expression of proliferating cell nuclear antigen (PCNA), paired box 7 (PAX7), myogenic factor 5 (MYF5), and myogenic differentiation factor (MYOD) did not differ between groups (P ≥ 0.327). However, IGF2-specific mRNA expression was numerically higher in the HP piglets (P = 0.101). The greater myofiber number, the higher degree of myofiber hypertrophy, and the increased muscular mRNA expression of IGF2 indicate that HP piglets exhibit a greater capacity for lean accretion and may grow faster until market weight. In summary, pigs that were selected for predicted high BW at 10 wk of age using a complex selection model had a superior muscularity in terms of greater TFN and FCSA, which may be of advantage for lean mass accretion in later life and for meat quality.

Dietary self-selection by broilers at normal and high temperature changes feed intake behavior, nutrient intake, and performance

Self-selection assumes that at high ambient temperature, birds are able to select a diet from different sources to minimize the heat load associated with the ingested nutrient metabolism. The objective was to test the hypothesis that young chickens are able to compose an adequate ration by adjusting dietary nutrient intake from 3 different diets that vary in energy and in protein contents from a cafeteria system at high temperature (HT; 31-32°C) and at normal temperature (NT; 31-21°C). Night temperature was set at 25°C at HT and at 18°C at NT and 12 h dark:12 h light. Control birds were fed a standard control diet (CP: 215 g/kg; ME: 2,895 kcal/kg) for broiler chickens. The choice-fed birds could choose between the control diet, a high-protein diet (CP: 299 g/kg; ME: 2,780 kcal/kg), and a high-energy diet (CP: 150.7 g/kg; ME: 3,241 kcal/kg). The diets had similar pellet size and color. Birds had access to each diet in a separate feeding trough from 1 to 42 d of age. Results showed that broilers spent 3.3% more time eating at NT than at HT and showed 42% more panting behavior at HT than at NT. High temperature decreased feed intake, protein intake, energy intake, and BW gain. Choice-fed birds had similar feed intake and BW gain, 14% lower protein intake, and 6.4% higher energy intake than control-fed birds. Body temperature and heterophil/lymphocyte ratio were higher at HT than at NT. Water intake was 8% higher in control-fed birds than in choice-fed birds but similar at both temperature regimens. It can be concluded that broilers can compose a diet by selecting less protein but higher energy density from different diets compared with the control. Choice-fed birds had similar feed efficiency as control-fed birds at HT, indicating similar body composition for both groups. Extra energy intake of choice-fed birds at HT was used for panting activity.

Postprandial oxidative losses of free and protein-bound amino acids in the diet: interactions and adaptation

Postprandial oxidation of dietary free amino acids or egg white protein was studied using the [13CO2] breath test in rats, as well as in humans. Thirty-eight male rats were assigned to four dietary test groups. Two diets only differed in their protein fraction. Diet I contained 21% egg white protein. For the breath test egg white protein, intrinsically labelled with [1-13C]-leucine, was used as a substrate. Diet II contained the same amino acids as diet I, though not as egg white protein but in free form. Free [1-13C]-leucine was used to label this diet. In addition, two 1:1 mixtures of both diets were used. During the breath test either the free amino acid or the protein fraction was labelled as in diets I or II. The animals were breath-tested following short-term (day 5) and long-term adaptation (day 20) to their experimental diet. For all diets, including the mixed diets, postprandial oxidative losses on day 5 were significantly higher for the free leucine compared with the protein-derived leucine. Differences between free and protein-derived leucine oxidation had, however, largely disappeared on day 20. The human subjects were breath-tested without any adaptation period to the diets. The oxidative losses of free leucine were also higher than those of protein-derived leucine. None of the studies showed any indication for an interaction between the oxidation of protein-derived amino acids and free amino acids. It is concluded that free and protein-derived amino acids in the diet are mainly metabolized independently.

Effect of dietary fat sources on fatty acid deposition and lipid metabolism in broiler chickens

The hypothesis tested was that dietary vegetable fats rich in saturated fatty acids, when compared with a vegetable oil rich in linoleic acid, increase fat deposition in broiler chickens and affect synthesis or oxidation, or both, of individual fatty acids. Diets with native sunflower oil (SO), a 50:50 mix of hydrogenated and native SO, palm oil, and randomized palm oil were fed to broiler chickens. Intake of digestible fat and fatty acids, whole body fatty acid deposition, hepatic fatty acid profile, and hepatic enzyme activities involved in fatty acid oxidation and synthesis were measured. The fat deposition:digestible fat intake ratio was significantly lower for the SO group in comparison with the groups fed the vegetable fats rich in saturated fatty acids. The difference between digestible intake and deposition of C18:2, reflecting its maximum disappearance rate, was highest for the SO group and lowest for the palm oil- and randomized palm oil-fed birds. The calculated minimal rate of de novo synthesis of monounsaturated fatty acids (MUFA), calculated as deposition minus digestible intake, was more than 50% lower for the SO group than for the other 3 dietary groups. Based on the fatty acid profiles in the liver, it would appear that increasing contents of C18:2 decrease the desaturation of saturated fatty acids into MUFA. It is concluded that a diet rich in C18:2 in comparison with different kinds of vegetable saturated fatty acids decreases the deposition of fat, especially of MUFA. It appears to be caused by a higher β-oxidation and a reduced de novo synthesis of MUFA, but this conclusion is not fully supported by the measured activities of enzymes involved in fatty acid synthesis and oxidation.

Dietary balanced protein in broiler chickens. 1. A flexible and practical tool to predict dose–response curves

An empirical model of exponential form was developed, different versions of which can be used to predict growth rate, feed conversion and carcase and breast meat yield of broiler chickens as a function of dietary balanced protein (DBP) content. The model was developed to support decision-making by nutritionists. The model helps in determining DBP contents that maximise profit. The model avoids the practical disadvantages of existing methods. In contrast with mechanistic models, only data that are generally known by broiler nutritionists are required as input. Compared with predictions derived from one or a few feeding trials, the model predictions are more accurate (because the model was derived from many data-sets) and more flexible (because a description of the type of broiler was included as input for the model). Broiler response studies from the literature and the Nutreco Poultry and Rabbit Research Centre (27 data-sets in total) were used in the model development to select significant variables, to quantify the parameters and to evaluate the accuracy of the predictions. Input variables were DBP content, maximum performance level, age, year (indicating genetic potential) and sex. The model, including the assumption that the shape of the dose-response curves to DBP content is independent of broiler and feed characteristics, gave an accurate simulation of growth rate, feed conversion and breast meat for nearly all data-sets. Effects of DBP content on carcase yield were relatively small, except for carcases without skin and skin fat.

Dietary amino acid levels and feed restriction affect small intestinal development, mortality, and weight gain of male broilers

This study investigated the effect of 2 different dietary amino acid treatments and feed restriction in early life versus a control treatment on development of the small intestine segments (weights), mortality, and broiler performance. Each treatment was applied to 6 cages with Ross 308 male broilers and to 6 cages with Cobb 500 male broilers with 24 birds per cage. A control treatment (100% ideal protein) was compared with a treatment with 30% extra ideal protein, a treatment with daily adjustment of the dietary amino acid level and profile, and a feed restriction treatment. The protein treatments were applied from 0 to 14 d of age. The feed restriction was applied from 4 to 21 d of age. Restriction was 15% from d 4 to 14 of age and diminished with equal daily steps thereafter to 5% at 21 d of age. Birds were weighed and dissected for evaluation of small intestine weights at 6, 9, 14, and 36 d of age. Feed intake restriction reduced leg problems in Ross and Cobb broilers. Extra dietary protein reduced leg problems in Ross broilers only. The present experiment does not show that small intestinal weight development is related to mortality. Thirty percent extra dietary ideal protein increased duodenum weight between 6 and 9 d of age. This was not further increased by the daily optimization of the dietary amino acid level and profile. The increased duodenum weights coincided with an improved BW gain. This indicates that duodenum weight may be important in facilitating BW gain in young broilers. Thus, it may be worthwhile to pay more attention to the relation between nutrition and duodenum weight and duodenum function in further studies.

Wheat starch digestion rate affects broiler performance

Two experiments were conducted to determine the differences in starch digestion rate (KDS) among wheats from different cultivars and origins and to verify if chickens would benefit from a certain digestion rate of starch. In the first experiment, 192 chickens (21 d) were assigned to 4 diets containing 55% of each wheat sample (3 cultivars, one of them from 2 origins). Starch and protein digestion were calculated from the remaining starch and protein in 4 segments of the small intestine and in excreta, using chromic oxide as a marker. Mean retention time was measured in each segment, which enabled calculations of digestion rates. In the second experiment, 2,600 chickens were assigned to 5 isoenergetic and isonitrogenous diets (with KDS from 1.80 to 2.56 h(-1)) and growth performance was determined (1 to 34 d). In 3 treatments, dietary starch was provided each by the wheat cultivars (same origin), whereas in the other 2 treatments, 25 and 50% of the wheat starch with the highest KDS was substituted by pea starch. Clostridium perfringens and Lactobacillus in the cecal chyme and glucose in the blood (glycemic index) were measured in broilers at d 19 and 25, respectively. Starch was gradually digested along the small intestine, mainly in the jejunum (48.5 and 80.4% at proximal and distal jejunum) where the largest differences among wheat samples were found. Starch digestion rate varied with origin (from 1.96 to 2.56 h(-1)) and cultivar (from 2.17 to 2.56 h(-1)). Crude protein digestion rate (average 2.21 h(-1)) was not affected by either cultivar or origin. Broiler growth and feed conversion ratio improved in a quadratic way with KDS. The maximum broiler performance was observed with KDS around 2.2 h(-1). Blood glucose response (glycemic index) was not affected by KDS; therefore, it cannot be used to predict broiler performance. In conclusion, the rate of starch digestion varies among wheats, depending on both genetic and environmental conditions of the grain, and affects broiler performance.

Effects of nutrient dilution and nonstarch polysaccharide concentration in rearing and laying diets on eating behavior and feather damage of rearing and laying hens

An experiment was conducted with 768 non-cage-housed ISA Brown pullets, of which 576 hens were followed during the laying period, to investigate the separate effects of dietary energy dilution and non-starch polysaccharides (NSP) concentration (oat hulls as NSP source) on eating behavior and feather damage. Day-old pullets were allotted to 1 of 6 dietary treatments according to a 3 x 2 factorial arrangement (3 dilution and 2 NSP levels), with 8 replicates (pens) per treatment. At 17 wk of age, pens with hens were allotted to 1 of 8 dietary treatments according to a 4 x 2 factorial arrangement (4 dilution and 2 NSP levels), with 6 replicates per treatment. Compared with 0% dilution level, feed intake of laying hens of 10, 15, and 20% dilution levels increased by 8.4% (9.5 g/hen per d), 16.5% (18.1 g/hen per d), and 20.9% (23.6 g/hen per d), respectively. The ME(n) intake was similar for all dilution levels. Hens fed standard-NSP laying diets had similar insoluble NSP intake for all dilution levels (9.3 g/hen per d). Insoluble NSP intake of hens fed high-NSP laying diets increased from 15.6 g/hen per day (0% dilution) to 18.9 g/hen per day (20% dilution). Providing high- vs. standard-NSP layer diet decreased relative proventriculus contents (1.1 vs. 0.3 g/kg of BW) and increased empty gizzard weight (14.3 vs. 24.4 g/kg of BW). Hens that were fed standard-NSP diets had more feather damage compared with hens fed high-NSP diets (0.58 vs. 0.30 arbitrary units). Increasing the insoluble NSP intake resulted in decreased proventricular weight and increased gizzard weight and its contents, which are indicators of improved functioning of the gut, thereby linearly reducing feather damage. Providing diluted rearing diets increased feed intake from the first weeks of life onwards. It was hypothesized that pullets were increasingly "imprinted" on feed as pecking substrate if dilution level increased. This may decrease feather pecking and could explain the improved feather condition at 49 wk of age when 15% diluted rearing diet was fed.

Effect of wheat cultivar and enzyme addition to broiler chicken diets on nutrient digestibility, performance, and apparent metabolizable energy content

A total of 5,000 one-day-old male broiler chickens were assigned to 8 different treatments in a 4 x 2 factorial design. Four wheat cultivars (Amiro, Guadalupe, Isengrain, and Horzal) and 2 levels (0 or 1 kg/t of feed) of an enzyme cocktail (Avizyme 1300, xylanase, 2,500 U/kg and protease, 800 U/kg) were used. Nutritionally complete mash diets contained 65 and 70% of the test wheat for the starter and grower period, respectively. Test wheats were used in diets for broilers, and growth performance and AME contents were measured. Broiler performance was measured in 4,800 broilers allocated to floor pens with 75 birds each and fed from 1 to 42 d of age. Digestibilities and AME contents of diets were measured in 200 broilers from 6 to 27 d of age individually allocated to battery cages. Chromic oxide (Cr(2)O(3)) at an inclusion rate of 0.5% in the diet was used as an indigestible marker. Apparent metabolizable energy was corrected by zero N balance to obtain AME(n). Wheat cultivar strongly influenced animal performance during the starter period (1 to 21 d of age). During the grower period (21 to 42 d of age), only BW and daily feed intake were influenced by wheat cultivar. Differences in daily feed intake were associated with differences in AME(n) intake during the starter period, but not during the grower period. Nutrient digestibility was higher with the use of enzyme. Animal performance was not affected (i.e., wheat cultivar differences were not eliminated by using enzymes). During the grower period, significant interactions were detected with regard to nutrient digestibility and AME(n). Differences in AME(n) content of wheat could not be explained by digestible starch.

Comparative in vitro fermentation activity in the canine distal gastrointestinal tract and fermentation kinetics of fiber sources

The current study aimed to evaluate the variation in fermentation activity along the distal canine gastrointestinal tract (GIT, Exp. 1). It also aimed to assess fermentation kinetics and end product profiles of 16 dietary fibers for dog foods using canine fecal inoculum (Exp. 2). For Exp. 1, digesta were collected from the distal ileum, proximal colon, transverse colon, and rectum of 3 adult dogs. Digesta per part of the GIT were pooled for 3 dogs, diluted (1:25, wt/vol), mixed, and filtered for the preparation of inoculum. A fructan, ground soy hulls, and native potato starch were used as substrates and incubated for cumulative gas production measurement as an indicator of the kinetics of fermentation. In addition, fermentation bottles with similar contents were incubated but were allowed to release their gas throughout incubation. Fermentation fluid was sampled at 4, 8, 12, 24, 48, and 72 h after initiation of incubation, and short-chain fatty acids and ammonia were measured. Results showed comparable maximal fermentation rates for rectal and proximal colonic inocula (P > 0.05). Production of short-chain fatty acids was least for the ileal and greatest for the rectal inoculum (P < 0.05). Therefore, for in vitro studies, fecal microbiota can be used as an inoculum source but may slightly overestimate in vivo fermentation. Experiment 2 evaluated the gas production, fermentation kinetics, and end product profiles at 8 and 72 h of incubation for citrus pectin, 3 fructans, gum arabic, 3 guar gums, pea fiber, peanut hulls, soy fiber, sugar beet fiber, sugar beet pectin, sugar beet pulp, wheat fiber, and wheat middlings. Feces of 4 adult dogs were used as an inoculum source. Similar techniques were used as in Exp. 1 except for the dilution factor used (1:10, wt/vol). Among substrates, large variations in fermentation kinetics and end product profiles were noted. Sugar beet pectin, the fructans, and the gums were rapidly fermentable, indicated by a greater maximal rate of gas production (R(max)) compared with all other substrates (P < 0.05), whereas peanut hulls and wheat fiber were poorly fermentable, indicated by the least amount of gas produced (P < 0.05). Sugar beet fiber, sugar beet pulp, soy fiber, and wheat middlings were moderately fermentable with a low R(max). Citrus pectin and pea fiber showed a similar low R(max), but time at which this occurred was later compared with sugar beet fiber, sugar beet pulp, soy fiber, and wheat middlings (P < 0.05). Results of this study can be used to formulate canine diets that stimulate dietary fiber fermentation along the distal GIT that may optimize GIT health and stimulate the level of satiety in dogs.

Low dietary energy concentration, high nonstarch polysaccharide concentration, and coarse particle sizes of nonstarch polysaccharides affect the behavior of feather-pecking-prone laying hens

An experiment was conducted with 504 non-cage-housed ISA Brown laying hens from 18 to 40 wk of age to investigate the separate effects of dietary energy concentration, nonstarch polysaccharide (NSP) concentration, and particle sizes of added NSP source on the eating behavior, feather-pecking behavior, and hen performance of laying hens. Hens were allotted to 1 of 6 dietary treatments according to a 2 x 3 factorial arrangement, with 7 replicates per treatment. The factors were control and low energy concentration (2,825 vs. 2,540 kcal/kg), control and high NSP concentration (133 vs. 195 g/kg), and fine vs. coarse particle size of the added NSP source in the high-NSP diets. We hypothesized that eating time would be increased by feeding low-energy diets or coarsely ground, high-NSP diets, or both, resulting in reduced feather-pecking behavior, without negatively affecting hen performance. Energy reduction, NSP addition, and coarse grinding of NSP increased eating time by 14.2% (P = 0.001), 17.2% (P < 0.001), and 7.9% (P = 0.075), respectively, compared with the control level of these factors. Addition of NSP decreased eating rate (g/min) by 21.0% (P = 0.010). Layers already performed gentle feather-pecking behavior during the fifth week of the rearing period. Dietary treatments did not affect the maximal level of feather condition scores, but arise of feather damage was delayed by 10 wk in hens fed low-energy, coarsely ground, NSP-rich diets compared with hens fed control diets. Hens fed the control NSP diets showed reduced culling rates, because of less cannibalistic pecking, when energy concentration was decreased (44.1 vs. 13.1%), whereas in the high-NSP diets, culling rate decreased slightly when hens were fed the low-energy diets (31.6 vs. 28.6%; P = 0.071). Hens that were fed the low-energy diets compensated for the 10% reduction in energy concentration by a 9.3% higher maximal feed intake (143.0 vs. 130.8 g/d). Hen performance and BW gain of the hens were not affected by dietary treatments. We concluded that hens that were fed low-energy or high (coarsely ground)-NSP diets spend more time on feed intake, compared with hens that were fed the control diets. As a result, hens in some treatments showed less feather-pecking behavior.

Evaluation of diabetes determinants in woolly monkeys (Lagothrix lagotricha)

Woolly monkeys (Lagothrix lagotricha) are a threatened specie in the wild with limited successful management in captivity due to diagnosed hypertension and suspected diabetic conditions. Six woolly monkeys with known hypertension problems were tested to determine if diabetes mellitus and current daily diet are underlying links to health problems for the captive population of this species. Blood and urine were collected and serum was analysed for fructosamine, glucose, glycated haemoglobin, insulin, triacylglycerides, total cholesterol, high-density lipoprotein cholesterol (HDL-Chol) and low-density lipoprotein cholesterol (LDL-Chol) while urine was tested for glucose concentrations. Diet disappearance was determined for 3 days prior to blood collection and nutrient content was calculated using Zoo Diet Analysis computer program. Serum analyses were within normal ranges (fructosamine (139-242 micromol/l), glucose (2.22-4.78 mmol/l), glycated haemoglobin (3.52-4.73%), insulin (6.2-13.0 microU/ml), triacylglycerides (0.38-3.4 mmol/l), total cholesterol (2.5-5.1 mmol/l), HDL-Chol (0.4-1.6 mmol/l) and LDL-Chol (1.8-3.4 mmol/l)). Urine glucose concentrations were below the detection limit. Diets were not limiting in starch and total sugars and were similar in non-starch polysaccharides. Potential dietary deficiencies were noted for vitamin A, vitamin D, calcium, phosphorus and selenium. When compared with the available primate reference ranges, the results do not indicate problems with diabetes mellitus or with glucose metabolism and therefore they are not causes of the diagnosed hypertension. Further research to ascertain the true cause of health related problems and the role of dietary factors is needed.

Effect of nutrient dilution on feed intake, eating time and performance of hens in early lay

1. An experiment with 480 ISA Brown layers was conducted to measure the effect of dietary energy (11.8, 11.2 and 10.6 MJ/kg) and non-starch polysaccharides (NSP) (128, 146 and 207 g/kg) concentration, soluble NSP content (64 and 85 g/kg), particle size distribution of the NSP fraction (fine and coarse) and feed form (mash and crumble) on feed intake, eating time and egg performance of laying hens in early lay (from 18 to 26 weeks of age). Twelve experimental diets were tested, each replicated 4 times. 2. Laying hens in early lay that were fed low- or high-NSP diets were able to compensate for 10% dietary dilution by 9.5 and 4.9% higher feed intakes, respectively. Feeding crumble or coarsely ground mash did not affect feed intake. 3. Eating time of the hens fed the undiluted diets increased over the experimental period from 16.4 to 24.6% of the observation period, but was not affected by sand or grit addition, particle size distribution or feed form. Feeding high-NSP diets increased eating time by 22%. 4. Egg performance and body weight gain of the hens that were fed low-NSP or high-NSP diets were similar or better compared to the undiluted diets, whereas coarse grinding of the diets showed 7 to 10% lower egg performance and weight gain. Egg performance and weight gain were not affected by feed form. 5. It is concluded that hens in early lay, fed energy-diluted diets, by adding sand or grit (low-NSP) or NSP-rich raw materials (high-NSP) to the control diet, were able to increase their feed intake, resulting in energy intake and egg performance comparable to the control group. Supplementing diets with insoluble NSP also decreased eating rate. Prolonged eating time using insoluble NSP could be useful in reducing feather pecking behaviour.

The effect of low-density diets on broiler breeder development and nutrient digestibility during the rearing period

Low-density diets might help to reduce hunger feeling in restricted-fed broiler breeders. Effects of low-density diets on nutrient digestibility and bird development were studied in Cobb 500 broiler breeder hens from 4 wk of age until the onset of the lay (wk 26). The experiment included 4 treatments. The control treatment was a normal density diet (ND; 2,600 kcal/kg). Treatments 2 and 3 had a 12 and 23% lower nutrient density than ND (LD12 and LD23, respectively) through inclusion of palm kernel meal, wheat bran, wheat gluten feed, and sunflower seed meal. Treatment 4 also had a 12% lower nutrient density than ND but included oats and sugar beet pulp (LD12(OP)). Total daily intake of energy, digestible lysine, calcium, retainable phosphorus, sodium, and linoleic acid was kept constant in the low-density dietary treatments. Animal performance and development of the intestinal tract and reproductive tract were determined in addition to digestibility and feed passage rate. The LD12(OP) provided a lower AME and nutrient digestibility than calculated and was related to lower live weights. Birds given LD23 and LD12(OP) showed a faster ovarian and oviduct development between wk 24 and 26 compared with ND. At 22 wk of age, LD23 and LD12(OP) diets resulted in higher empty jejunum and ileum weights. Low-density diets did not affect intestinal tract contents and decreased mean retention time of the contents. It was concluded that low-density diets can affect live weight and development of digestive and reproductive tracts.

Effects of increasing temperatures on physiological changes in pigs at different relative humidities

The effects of relative humidity (RH) and high ambient temperature (T) on physiological responses and animal performance were studied using 12 groups (10 gilts per group) in pens inside respiration chambers. The microclimate in the chamber was programmed so that T remained constant within a day. Each day, the T was increased by 2 degrees C from low (16 degrees C) to high (32 degrees C). Relative humidity was kept constant at 50, 65, or 80%. The pigs' average initial BW was 61.7 kg (58.0 to 65.5 kg), and their average ending BW was 70.2 kg (65.9 to 74.7 kg). Respiration rate (RR), evaporative water (EW), rectal temperature (RT), skin temperature (ST), voluntary feed intake (VFI), water-to-feed ratio (rW:F), heat production (HP), and ADG were analyzed. The animals had free access to feed and water. We determined the T above which certain animal variables started to change: the so-called inflection point temperature (IPt) or "upper critical temperature." The first indicator of reaction, RR, was in the range from 21.3 to 23.4 degrees C. Rectal temperature was a delayed indicator of heat stress tolerance, with IPt values ranging from 24.6 to 27.1 degrees C. For both these indicators the IPt was least at 80% RH (P < 0.05). Heat production and VFI were decreased above IPt of 22.9 and 25.5 degrees C, respectively (P < 0.001). For each degree Celsius above IPt, the VFI was decreased by 81, 99, and 106 g/(pig.d) in treatments 50, 65, and 80% RH, respectively. The ADG was greatest at 50% RH (P < 0.05). Ambient temperature strongly affects the pigs' physiological changes and performance, whereas RH has a relatively minor effect on heat stress in growing pigs; however, the combination of high T and high RH lowered the ADG in pigs. The upper critical temperature can be considered to be the IPt above which VFI decreased and RT then increased. Temperatures of the magnitude of both these IPt are regularly measured in commercial pig houses. We conclude that the upper critical temperatures for 60-kg, group-housed pigs fed ad libitum are between 21.3 and 22.4 degrees C for RR, between 22.9 and 25.5 degrees C for HP and VFI, and between 24.6 and 27.1 degrees C for RT. It is clear that different physiological and productive measurements of group-housed, growing-finishing pigs have different critical temperatures.

The Effect of Low-Density Diets on Broiler Breeder Performance During the Laying Period and on Embryonic Development of their Offspring

The effect of low-density diets on bird performance, egg composition, and embryonic development was studied with 2,100 female and 210 male Cobb broiler breeders from 25 to 60 wk of age. The experiment included 5 treatments. These included a control group with a normal density diet (ND, 2,800 kcal of AME/kg). Treatments 2 (LD11) and 3 (LD21) had a 11 and 21% lower nutrient density. Treatment 4 (LD11(OP)) had a 11% less dense diet, which was obtained by inclusion of other feed ingredients. In these 4 treatments similar diets were given during the rearing and the laying period. Treatment 5 combined LD12 in the rearing period and ND diets during the laying period (LD12-ND). Egg composition and embryonic development were measured in eggs of ND and LD21 birds at 29 and 41 wk of age. During the laying period from wk 25 to 60, live weights did not differ among treatments, except that birds fed LD11(OP) had lower live weights. A significantly higher rate of lay was provided by LD11 compared with ND. Egg weights were significantly higher when low-density diets were fed, particularly in LD11(OP). Percentage of fertile eggs did not differ among treatments. Compared with the other treatments, LD11(OP) provided a significantly lower hatchability. We found that LD21 resulted in a better development of the area vitellina externa and heart and embryo weight at 29 wk of age. It was concluded that this was related to a higher egg weight and egg white proportion. This suggests that the amount of egg white in eggs of hens fed ND was limiting for embryonic development, particularly in eggs of young broiler breeders.

The effect of low-density broiler breeder diets on performance and immune status of their offspring

Effects of low-density broiler breeder diets on offspring performance and mortality were studied using 2,100 female and 210 male Cobb 500 breeders. Breeder treatments involved 4 experimental groups and a control group with normal density diets (ND, 2,600 kcal of AME/kg during rearing and 2,800 kcal of AME/kg during laying). In treatment 2, nutrient densities were decreased by 12% (LD12) and 11% (LD11) during the rearing and laying periods, respectively, whereas in treatment 3, nutrient densities were decreased by 23% (LD23) and 21% (LD21) during the rearing and laying periods, respectively. The nutrient density in these treatments was decreased through inclusion of palm kernel meal, wheat bran, wheat gluten feed, and sunflower seed meal in the diets. Treatment 4 included diets with the same nutrient densities as in treatment 2 but included oats and sugar beet pulp (LD12(OP) and LD11(OP)). In treatment 5, the same low-density diet was given to the breeders as in treatment 2 during the rearing period, but it was followed by a normal density diet during the laying period (LD12-ND). Treatments were applied from 4 to 60 wk of age. On low-density diets, offspring showed an increased 1-d-old weight. As compared with offspring of breeders that received ND, the d 38 live weight of chickens from 29-wk-old breeders fed LD11 was improved. Mortality was reduced in offspring from 60-wk-old parent stock given low-density diets. The IgM titers in 35-d-old offspring from eggs with a lower-than-average weight were reduced when 29-wk-old broiler breeders were fed low-density diets. In offspring from eggs with a higher-than-average weight from 60-wk-old parent stock given LD11 or LD21 diets, IgM titers were higher compared with ND. It was concluded that low-density broiler breeder diets can improve offspring growth rates, reduce mortality, and reduce or increase immune responses, depending on breeder age and egg weight.

Modelling of nutrient partitioning in growing pigs to predict their anatomical body composition. 2. Model evaluation

The objective of the present paper was to evaluate a dynamic mechanistic model for growing and fattening pigs presented in a companion paper. The model predicted the rate of protein and fat deposition (chemical composition), rate of tissue deposition (anatomical composition) and performance of pigs depending on nutrient intake. In the model evaluation, the predicted response of the pig to changes in model parameters and to changes in nutrient intakes is presented. As a result of the sensitivity analysis, changes in the maintenance energy requirements and the fractional degradation rate of muscle protein had the greatest impact on tissue deposition rates. The model was also highly sensitive to changes in the maximum velocity and steepness parameter of the lysine utilisation for muscle protein synthesis. The model was further tested by independent published results. The model successfully predicted the response of pigs to a wide range of variation in nutrient composition. Consequently, the model can be applied to develop feeding strategies to optimise pig production. It also enables prediction of the slaughter performance and the meat quality.

Modelling of nutrient partitioning in growing pigs to predict their anatomical body composition. 1. Model description

A dynamic mechanistic model was developed for growing and fattening pigs. The aim of the model was to predict growth rate and the chemical and anatomical body compositions from the digestible nutrient intake of gilts (20–105 kg live weight). The model represents the partitioning of digestible nutrients from intake through intermediary metabolism to body protein and body fat. State variables of the model were lysine, acetyl-CoA equivalents, glucose, volatile fatty acids and fatty acids as metabolite pools, and protein in muscle, hide–backfat, bone and viscera and body fat as body constituent pools. It was assumed that fluxes of metabolites follow saturation kinetics depending on metabolite concentrations. In the model, protein deposition rate depended on the availability of lysine and of acetyl-CoA. The anatomical body composition in terms of muscle, organs, hide–backfat and bone was predicted from the chemical body composition and accretion using allometric relationships. Partitioning of protein, fat, water and ash in muscle, organs, hide–backfat and bone fractions were driven by the rates of muscle protein and body fat deposition. Model parameters were adjusted to obtain a good fit of the experimental data from literature. Differential equations were solved numerically for a given set of initial conditions and parameter values. In the present paper, the model is presented, including its parameterisation. The evaluation of the model is described in a companion paper.

Villus height and gut development in weaned piglets receiving diets containing either glucose, lactose or starch

The present study was designed to evaluate the differential effects of dietary glucose, lactose and starch on small-intestinal morphology, organ weights, pH of chyme and haptoglobin levels in blood plasma of weaned piglets. It was hypothesised that lactose consumption would ameliorate the weaning-induced decrease in gut integrity. A total of forty-two barrows were used. Piglets were weaned at 27 (sd 0·8) d of age and weighed 8·0 (sd 0·51) kg. On the day before weaning (day −1) all pigs were blocked according to body weight and randomly assigned to seven groups (n 6 per group). The groups differed in diet and day of dissection. On the day of weaning, dissection was performed on one group of six piglets. The remaining groups were fed one of three experimental diets in which glucose, lactose or starch had been iso-energetically exchanged, supplying 24% dietary energy. The piglets received a liquid diet (air-dry meal:water of 1:2, w/w). The piglets were given access to a maximum of dietary energy in order to prevent confounding between feed intake and villus architecture. The piglets were dissected and sampled on days 0, 3, or 10 post-weaning. The results show that the carbohydrate source did not affect growth performance, organ weights, villus architecture, pH of chyme and plasma haptoglobin level. The weaning transition resulted in decreased villus height and increased haptoglobin levels. In the contents of the caecum and large intestine, the pH decreased after weaning. It is concluded that at least under conditions of similar feed intake and low infectious pressure, dietary lactose does not ameliorate the weaning-induced compromise of small-intestinal integrity when compared with either glucose or starch.

The effect of previous growth retardation on energy and nitrogen metabolism of goats infected with Trypanosoma vivax

The effect of growth retardation, resulting from feed restriction for a prolonged period, on the course of infection with Trypanosoma vivax was studied. Twelve male castrated West Africa Dwarf goats were subjected to a restricted feeding reghen of 55 g pelleted lucerne (Medicago safiva)/kg body weight0·75 per d for on average 17 weeks. Twelve other animals were fed on pelleted lucerne ad libitum, resulting in a normal growth pattern. After this period, all animals were fed on pelleted lucerne ad libitum, and six animatn of each previous feeding regimen treatment were infected with Trypanosoma viva. The other animals served as controls. In week 2 and 4 post infection (pi) energy and N balaoces were measured. In the week before infection and daring infection blood biochemical and clinlcal variables were measured. At 2 weeks before, and 4 weeks after infection, a liver biopsy was taken for measurement of triacylglycerol. Iofection caused intermittent fever and anaemia. The first peak of fever persisted longer in iofected anlmaln with normal growth than in infected animals with retarded growth. Gross energy and metabolizable energy intake, and energy retention were reduced ininfected animals. Metabolizable energy requirements for mainteoaoce were increased by infection. Plasma non-esterified fatty acids (NEFA) and glucose concentratioos were increased in infected animals, whereas serum triiodothyronine and thyroxine coocentratioos were decreased.Plasma urea concentration and liver triacylglycerol were uoaffected. No interaction of growth retardation with infection with respect to blood biochemical variables was found, apart from plasma NEFA in week 2 pi. N retention was not significantly affected by treatments. In conclusion, minor indications were found for an interaction between growth retardation, as applied in the present study, and trypaommiasis infection in West Africao Dwarf goats with respect to energy and N metabolism.

Application of inulin-type fructans in animal feed and pet food

The inulin-type fructans are non-digestible oligosaccharides that are fermented in the gastrointestinal tract of farm animals and pets. This review focuses on the various effects of inulin-type fructans in pigs, poultry, calves and companion animals. Effects of the inulin-type fructans on gut microflora, digestion and availability of nutrients, gut morphology, fermentation characteristics and animal performance are discussed. Inulin-type fructans can support animal performance and health by affecting nutrient digestion, gut microflora and gut morphology, although results vary depending on composition of the basal diet, inclusion level, type of fructan, adaptation period and experimental hygienic conditions.