Contribution of purified soybean trypsin inhibitor and exogenous protease to endogenous amino acid losses and mineral digestibility

The primary objective of the current study was to evaluate the impact of trypsin inhibitor (TI) and exogenous protease supplementation on endogenous loss of amino acids (AA) in broiler chickens. A total of 384 Cobb-500 broiler chicks were allocated to 4 nitrogen-free diets, each with 8 replicate cages and 12 birds per replicate. The diets were arranged as a 2 × 2 factorial with factors being dietary TI (0 or 8,000 TIU/g) and exogenous protease (0 or 15,000 PROT/kg). Desired dietary TI concentration was achieved by addition of commercially available, purified soybean TI. There was no effect of TI or exogenous protease or their interaction on growth performance of birds. However, the endogenous loss of nitrogen (N) and all AA increased (P < 0.05) due to dietary TI concentration except for Cys. The increase in endogenous AA due to TI ranged from 17% for Thr to 52.2% for Trp. Exogenous protease had no effect on endogenous loss of N and all AA. There was no effect of TI or exogenous protease or their interaction on the AID of P, however AID of Ca, Fe, Mg, Mn, and Cu was reduced (P < 0.05) due to dietary TI. The AID of Cu (P < 0.01) and K (P < 0.05) improved with exogenous protease supplementation. Significant interactions (P < 0.05) between exogenous protease and TI existed for Zn, Mg, Cu, and Na. The concentration (g/kg DM intake) of crude mucin and sialic acid increased (P < 0.05) with increased dietary TI. Decreased trypsin (P < 0.001) and increased chymotrypsin (P < 0.001) activity in the pancreas were observed as a result of exogenous protease supplementation. In conclusion, the current study showed that TI increases the endogenous loss of AA and reduced the digestibility of minerals in broiler chickens. Furthermore, exogenous protease did not affect endogenous AA flow, irrespective of added purified dietary TI.

Dietary phosphorus level regulates appetite through modulation of gut and hypothalamic expression of anorexigenic genes in broiler chickens

Two experiments were designed to elucidate gut and hypothalamic molecular regulation of appetite by dietary phosphorus (P) concentration in broiler chickens. Birds (192 Cobb-500 broiler chickens) were randomly assigned to 3 experimental diets in experiment 1 (Exp. 1) and 24 broiler chickens were randomly assigned to 3 treatment groups in Exp. 2. Each diet comprised 8 replicate cages, with either 8 birds (Exp. 1) or 1 bird (Exp. 2) per replicate cage. In Exp. 1, diets contained 1.2 (P-deficient), 2.8 (P-marginal) or 4.4 (P-adequate) g/kg non-phytate P (nPP). In Exp. 2, birds fed the P-adequate diet were pair-fed (PF) to the feed consumption levels of birds fed the P-deficient diet. Feed intake and BW gain (P < 0.001) decreased in birds fed the P-deficient diet in Exp. 1. Birds fed the P-deficient diet had similar feed intake and BW gain with PF group fed the P-adequate diet (Exp. 2) but was significantly lower (P < 0.001) than birds fed the P-adequate diets. Sodium-phosphate cotransporter (NaPi-IIb) mRNA was upregulated (P < 0.05) in both experiments. Conversely, cholecystokinin (CCK) mRNA was downregulated (P < 0.01) in birds fed P-deficient diets. Anorexia-related hypothalamic cholecystokinin receptor (CCKAR) and melanocortin receptors (MC3R and MC4R) were upregulated (P < 0.05) in birds fed P-deficient diets, in both experiments. The current data show that dietary P deficiency decreases feed intake in broiler chickens by altering the expression of anorexigenic genes in the gut and hypothalamus of broiler chickens.

Adipose tissue-specific responses reveal an important role of lipogenesis during heat stress adaptation in pigs

Elevated ambient temperature causes heat stress in pigs, resulting in reduced animal performance. To better understand tissue responses to heat stress in pigs, we conducted a study in which pigs were subjected to four treatments: acute (24 h) heat stress (AHS) at 35 °C ± 1 ambient temperature, chronic (7 d) heat stress at 35 °C ± 1 (HS) or normal ambient temperature (20 °C± 1) for 7 d with ad-libitum feeding (Con) or with pair-feeding to the feed intake (FI) of the HS pigs (PF). Heat stress decreased FI by approximately 36% and 64% in HS and AHS treatments respectively, compared with Con (P < 0.01). Concentration of free fatty acids (FFA) was elevated in AHS compared to HS (P = 0.031). Serum insulin concentration was lower in PF than Con (P = 0.045). Blood urea nitrogen (BUN) concentration was elevated in HS compared with Con and PF (P = 0.008), but lower (P < 0.021) in AHS compared to HS. In the subcutaneous adipose tissue, the mRNA and protein abundance of PCK1 were higher (P < 0.05) in the HS treatment than Con and PF, and also higher (P < 0.05) in HS than AHS. However, there was no difference in GK mRNA between Con, PF, and HS, although its expression was lower (P = 0.003) in AHS vs. HS. Protein abundance of the ER stress marker, CCAT/enhancer-binding homologous protein (CHOP), was higher in PF than Con (P < 0.05), and higher (P = 0.033) in HS than AHS in subcutaneous fat. In mesenteric fat, PCK1 mRNA was higher (P < 0.001) in the HS than Con and PF treatments. Additionally, expression of PCK1 was lower (P = 0.039) in AHS vs. HS. Expression of PCK1 was downregulated (P < 0.05) in the liver of PF pigs compared to other treatments, but most other genes measured were not affected by treatment in the liver and muscle tissues. These results confirm that heat stress induces a robust adipose tissue response in favor of increased lipid storage. This indicates that adipose tissue might play an important role in heat stress adaptation.

Effect of threonine on secretory immune system using a chicken intestinal ex vivo model with lipopolysaccharide challenge

Secretory IgA (sIgA) and its transcytosis receptor, polymeric immunoglobulin receptor (pIgR), along with mucus, form the first lines of intestinal defense. Threonine (Thr) is a major component of intestinal mucins and IgA, which are highly secreted under lipopolysaccharide (LPS) induced inflammation. In the current study, the effect of Thr on the secretory immune system was determined in an ex vivo chicken ileal explant model. Results showed that a 2-hour Thr-deprivation of culture medium induced a compensatory increase in the mRNA expression of interleukin-8 (IL-8), mucin 2 (MUC2), and IgA during LPS challenge, and this increase was suppressed with Thr addition to the media (P ≤ 0.05), suggesting that Thr was required for mucin and IgA production after exposure to LPS. Similarly, a 2-hour culture of explants from birds fed a Thr adequate diet showed an increase in the mRNA abundance of IL-8, MUC2, and IgA with LPS treatment (P ≤ 0.003), which had a trend to be attenuated with Thr supplementation in the media (P ≤ 0.10). In contrast, explants from birds fed a Thr deficient diet had no response to LPS treatment. These results indicated that in vivo Thr deficiency induced impaired inflammatory and secretory immune responses in broiler chicks. Furthermore, our results revealed that induction of MUC2 and pIgR gene expression required nuclear factor-κB (NF-κB) activation. Additionally, IgA transcytosis may be dependent on extracellular-regulated protein kinase (ERK) activation, which may indirectly impact pIgR gene expression.

Investigation of carryover effect of prior fibre consumption on growth, serum and tissue metabolic markers in Ossabaw pigs fed a high-fat diet

Carryover effect of prior fibre consumption on metabolic markers was investigated. Treatments were arranged in 2 × 2 factorial with 2 fibre sources, 4% inulin or cellulose (Solka-Floc®) and fat levels (5 or 15%) for the low-fat diet (LFD) and high-fat diet (HFD) respectively. Pigs were fed the two fibre diets for the first 56d (nursery phase), and thereafter fed either the LFD or HFD containing no added fibre source from d56 to 140 (growing phase). Pigs on the HFD were heavier (p = .05) than those on LF (64.61 vs. 68.38 kg), regardless of prior fibre type consumed. Pigs that were fed cellulose during the nursery and later fed the HFD had the highest ADG (p < .05). Feeding the HFD resulted in higher back fat (BF) (13.41 and 18.18 ± 0.12 mm for LFD and HFD, respectively; p < .01). The HFD resulted in higher (p < .01) insulin (0.014 and 0.016 ± 0.001 mg/L for LF and HF respectively) and glucose (100.89 and 125.03 ± 4.39 mg/dl for LF and HF respectively) concentrations in the serum. Inulin increased (p ≤ .02) jejunal expression of SREBP-1c and CL-4, but reduced (p < .05) TNFɑ and IL-6 expression in the ileum. Alpha-diversity was significantly different (p < .05) between the inulin and cellulose fed pigs at the end of the nursery and finishing phases. Therefore, inulin feeding before a HFD may lead to reduction in ADG and inflammatory markers in the small intestine of pigs, and thus prevent future metabolic disorders.

Garlic diallyl disulfide and diallyl trisulfide mitigates effects of pro-oxidant induced cellular stress and has immune modulatory function in LPS-stimulated porcine epithelial cells

The objective of the current study was to determine if garlic-derived diallyl disulfide (DADS) and diallyl trisulfide (DATS) could mitigate oxidative and endotoxin stress, using an intestinal porcine epithelial cell (IPEC-J2) model. The experiment was arranged as a 2 × 2 × 2 factorial of DADS + DATS (0 or 18 µM), pro-oxidant stressor (hydrogen peroxide at 0 or 100 µM), and endotoxin stressor (lipopolysaccharide [LPS] at 0 or 10 µg/mL) with 8 replicates per treatment. Cells were incubated with DADS + DATS for 18 h, LPS for 6 h, then with hydrogen peroxide for 3 h. Gene expression was measured by RT-PCR for cytokines, interleukin 8 (IL-8) and tumor necrosis factor α (TNF-α), and tight junction proteins, claudin 1 (CL-1), occludin (OC), and zonula occludens 1 (ZO-1). Trans-epithelial electrical resistance (TEER), the antioxidant enzyme catalase, and apical secretion of IL-8 protein into the incubation medium was also measured. There was an increase ( < 0.01) in TNF-α and IL-8 gene expression due to LPS, although there was no effect of hydrogen peroxide or DADS + DATS. Furthermore, there was a tendency for an increase ( = 0.08) in ZO-1 gene expression due to DADS + DATS. Treatment with DADS + DATS and hydrogen peroxide did not affect TEER, although there was a decrease ( = 0.02) in TEER with LPS incubation. Treatment of cells with hydrogen peroxide reduced catalase activity ( < 0.01), which was restored with pre-incubation of DADS + DATS ( < 0.10). There was an increase ( < 0.01) in IL-8 secretion due to LPS, which was further augmented ( < 0.01) by pre-incubation with DADS + DATS. Based on the results from the current study, DADS + DATS can ameliorate oxidative effects of hydrogen peroxide, as well as alter IL-8 secretion in LPS-treated IPEC-J2 cells.

Ability of garlic-derived diallyl disulfide and diallyl trisulfide supplemented by oral gavage to mitigate effects of an acute postweaning feed and water deprivation event in nursery pigs

Compounds in garlic have been shown to contain anti-inflammatory, antioxidant, and immune modulatory properties that may be able to mitigate the effects of nursery pig stressors. The objective of the current experiment was to determine if oral gavage of garlic-derived diallyl disulfide (DADS) and diallyl trisulfide (DATS) could mitigate the effects of a 24-h postweaning feed + water deprivation event in nursery pigs. Pigs (6.0 ± 0.05 kg and 21 d old) were allotted to 4 treatments in a randomized complete block design at weaning with 8 replicate pens per treatment that consisted of with or without a 24-h postweaning feed + water deprivation event and with or without an oral gavage containing 3.6 mg DADS + DATS/kg BW. Growth performance and morbidity were recorded throughout the experiment, and on 1, 6, and 21 d after weaning, 1 pig per pen was selected, blood was collected, the pig was euthanized, and a segment of the distal ileum was subsequently excised for morphological and gene and protein expression measurements. Mucosal gene expression was conducted by reverse transcription PCR for immune, antioxidant, and cellular integrity markers. Furthermore, activity of mucosal superoxide dismutase was measured by colorimetric assay. Immediately following the feed + water deprivation event, there was a decrease ( < 0.01) in growth performance and an increase ( = 0.01) in serum cortisol. The feed + water deprivation event tended ( = 0.10) to decrease ileal villus height and supplementation of DADS + DATS by oral gavage increased ( = 0.03) villus height 1 d after weaning. Supplementation of DADS + DATS by oral gavage decreased ( = 0.03) and tended to decrease ( = 0.08) gene expression of on 6 and 21 d after weaning, respectively. Furthermore, at 1 d after weaning, ileal mucosa SOD activity was decreased ( = 0.01) by the feed + water deprivation and increased ( = 0.04) by oral supplementation of DADS + DATS. Expression of the tight junction genes and were reduced ( ≤ 0.05) due to the feed + water deprivation event 1 d after weaning. Results from the current study show that an acute feed + water deprivation event can impact growth performance, intestinal characteristics, and antioxidant status in nursery pigs, which can be partially mitigated by oral supplementation of garlic compounds DADS + DATS.

Heat stress in pigs is accompanied by adipose tissue-specific responses that favor increased triglyceride storage

Heat stress (HS) negatively affects all aspects of performance in pigs. Although certain tissue-specific responses in the liver, skeletal muscle, and intestine are known, there is paucity of information on responses within the adipose tissue. Therefore, the objective of this study was to delineate adipose tissue responses during HS in pigs. Thirty crossbred (Ossabaw × Duroc × Landrace) pigs were assigned to 3 treatments for 7 d. Treatments were 1) control and libitum fed (CON) with room temperature set at 20°C ± 1°C, 2) pair fed (PF) with room temperature as the CON treatment but pair fed to HS pigs, and 3) HS with room temperature 35°C ± 1°C and ad libitum access to feed. Compared with CON pigs, HS pigs had decreased feed intake and elevated skin temperature and respiration rate ( < 0.01). Blood urea nitrogen was higher ( = 0.01) in HS pigs compared with CON pigs only in males. In both subcutaneous and mesenteric adipose tissue, mRNA abundance of phosphoenolpyruvate carboxykinase (PCK1) was more elevated ( < 0.01) in HS groups compared with the CON and PF groups. Heat stress also caused increased heat shock protein 70 (HSP70; = 0.067) and CCAT/enhancer-binding homologous protein (CHOP) content ( < 0.05) in the mesenteric fat compared with the CON treatment. In conclusion, induction of PCK1 expression in adipose tissue by HS suggests elevated glyceroneogenesis might be involved in the increased fat storage in pigs under HS.

Effect on Rendement Napole genotype on metabolic markers in Ossabaw pigs fed different levels of fat

We investigated effects of Rendement Napole (RN) genotype on metabolic markers in Ossabaw pigs fed diets with different levels of dietary fat. Thirty-two pigs, belonging to either the wild-type (WT, rn⁺ /rn⁺ ) or carrier (CAR, RN^- /rn⁺ ) genotypes (n = 16/genotype), were divided into two dietary groups, (high fat [HF] or low fat [LF]) diets, for 12 weeks (n = 8 pigs/genotype/diet) after which pigs were killed for gene expression analysis by RT-PCR. Feeding HF diet caused increased daily gain (ADG, p < .05) and final body weight (BW) (p < .05) in comparison with the LF diet (p < .05). Feed efficiency (gain:feed) was higher (p < .05) in pigs on the HF and was higher (p < .05) in CAR pigs compared to WT. There was genotype × diet interaction (p = .05) on final BW such that CAR animals on LF diet had the same final BW as animals of both genotypes on HF diet. Carrier pigs on LF diet had higher (p < .05) average daily gain and gain:feed than WT pigs. There was a trend (p < .08) for a higher feed consumption in pigs on the LF diet. Backfat thickness was higher (p < .01) in pigs on the HF diet. Serum triglyceride was higher (0.62 vs. 0.33 mg/dl, p < .01) in pigs on HF diet. Serum insulin was higher (p < .05) in CAR versus WT pigs (0.40 vs. 0.015 μg/ml). Pigs on the HF diet had a higher (p < .05) serum insulin compared to those on the LF diet (0.032 vs. 0.023 μg/ml). Carnitine palmitoyl transferase 1-alpha was higher (p < .05) in the longissimus dorsi and semitendinosus muscles of pigs on HF diet. Acyl-CoA oxidase I was elevated (p < .05) in the liver of pigs on HF diet. Fatty acid synthase was lower in the longissimus dorsi muscle, liver and mesenteric fat (p < .05) of carrier pigs. The RN gene regulates specific metabolic markers in the Ossabaw pigs.

Interactive effects of dietary protein source and exogenous protease on growth performance, immune competence and jejunal health of broiler chickens

A total of 672 male 7-day-old broiler chicks were used in a 14-day cage study to evaluate the interactive effects of dietary protein source and exogenous protease on nutrient digestibility and intestinal physiology. Birds were fed a common starter diet from Days 0 to 7 and switched to experimental diets from Days 7 to 21. Four corn-based dietary treatments were arranged in a 2 × 2 factorial arrangement with factors being two major sources of protein [soybean meal (SBM) or canola meal] and diets offered with or without exogenous protease. Bodyweight gain and gain:feed were higher (P < 0.001) in the diets based on SBM than in the diets based on canola meal and protease was more effective (P < 0.05) in enhancing performance in SBM-based diets. Ileal nitrogen digestibility was increased (P < 0.01) by protease use in diets based on both major protein sources. However, ileal digestible energy was increased (P < 0.05) by protease only in the SBM-based diet resulting in an interaction between diet protein source and exogenous protease. Jejunal villus height tended to be higher (P = 0.07) in birds fed diets based on SBM and protease use increased (P < 0.05) crypt depth only in the SBM-free diets resulting in a significant interaction between protein source and protease use. Patterns of gene expression in jejunal tissue suggested that both dietary protein source and exogenous protease influence the expression of genes responsible for mucin secretion, amino acid transport and immune functionality in an age-dependent manner. It can be concluded that SBM may be a more suitable protein source for young broiler chickens than canola meal and that use of canola meal as a major source of dietary protein may have negative implications for performance, nitrogen digestibility and gut health. However, exogenous protease appears to be more compatible with substrates presented by SBM than is the case for canola meal based on advantages conferred in nutrient digestibility and performance. The beneficial effects of exogenous protease may be linked both to enhanced protein and energy digestibility and improved gut morphological characteristics, secretory and absorptive dynamics and immune resilience.

Effects of dietary resistant starch content on metabolic status, milk composition, and microbial profiling in lactating sows and on offspring performance

In the present study, the effects of dietary resistant starch (RS) content on serum metabolite and hormone concentrations, milk composition, and faecal microbial profiling in lactating sows, as well as on offspring performance was investigated. Sixteen sows were randomly allotted at breeding to two treatments containing low- and high-RS contents from normal and high-amylose corn varieties, respectively, and each treatment had eight replicates (sows). Individual piglet body weight (BW) and litter size were recorded at birth and weaning. Milk samples were obtained on day 10 after farrowing for composition analysis. On day 2 before weaning, blood and faecal samples were collected to determine serum metabolite and hormone concentrations and faecal microbial populations, respectively. Litter size at birth and weaning were not influenced (p > 0.05) by the sow dietary treatments. Although feeding the RS-rich diet to sows reduced (p = 0.004) offspring birth BW, there was no difference in piglet BW at weaning (p > 0.05). High-RS diet increased (p < 0.05) serum triacylglycerol and nonesterified fatty acid concentrations and milk total solid content, and tended (p = 0.09) to increase milk fat content in lactating sows. Feeding the RS-rich diet to sows increased (p < 0.01) faecal bacterial population diversity. These results indicate that high-RS diets induce fatty acid mobilization and a greater intestinal bacterial richness in lactating sows, as well as a greater nutrient density in maternal milk, without affecting offspring performance at weaning.

Butyrate supplementation to gestating sows and piglets induces muscle and adipose tissue oxidative genes and improves growth performance

Weaned pigs often experience growth reduction immediately after weaning due to multiple stress factors associated with weaning. We tested the effect of prenatal and postnatal butyrate supplementation on growth performance of piglets. In study 1, piglets were orally gavaged with 0.3% butyrate from day 4 after birth to weaning (day 21). Butyrate increased ADG by 13% compared to saline treated control. Expression of peroxisome proliferator activated receptor gamma coactivator 1 alpha (PGC-1α) was higher in muscle, adipose tissue, and ileum of butyrate-supplemented animals. Also, peroxisome proliferator activated receptor alpha (PPARα) was induced (P < 0.05) in the subcutaneous adipose tissue (SCAT) and muscle (longissimus dorsi [LD]) of butyrate-supplemented piglets. In vitro, butyrate increased (P < 0.05) fatty acid oxidation in primary adipocytes and suppressed basal lipolysis by 62% compared to untreated cells. Butyrate suppressed (P < 0.05) lipogenesis ((14)C-glucose incorporation into lipids) in adipocytes. This was accompanied by an approximately 30% reduction in the mRNA expression of fatty acid synthase (P < 0.05) in butyrate-treated cells vs. controls. Piglets born to sows that were supplemented with 0.3% butyrate during the last trimester of gestation had a 15% higher (P < 0.05) body weight at 12 wk than controls. In summary, butyrate supplementation to gestating sows and piglets enhanced postweaning growth performance, which may be mediated by increased substrate oxidation in butyrate treated animals.

Impact of exogenous carbohydrases and phytase on growth performance and nutrient digestibility in broilers

Lu, H., Adedokun, S. A., Preynat, A., Legrand-Defretin, V., Geraert, P. A., Adeola, O. and Ajuwon, K. M. 2013. Impact of exogenous carbohydrases and phytase on growth performance and nutrient digestibility in broilers. Can. J. Anim. Sci. 93: 243–249. The effect of supplementing corn–soybean-based diets with Rovabio®Max AP, an exogenous enzyme mix with carbohydrase (xylanase and β-glucanase) and phytase activities to broiler chickens was evaluated. Male Ross 708 broilers were assigned to four diets: positive control (PC), negative control (NC), deficient in metabolizable energy (ME), crude protein (CP), calcium (Ca) and non-phytate phosphorus (nPP), relative to the PC, by 100 kcal kg−1, 5 g kg−1, 1.1 g kg−1and 1.6 g kg−1, respectively, in the starter and grower diets; and NC+Rovabio®at 0.05 or 0.075 g kg−1diet. Starter diets were fed from day 0 to day 21 and grower diets from day 22 to day 42. Body weight (BW) and body weight gain on days 22 and 42 were increased (P<0.05) by enzyme supplementation. Enzyme addition increased (P<0.05) feed intake from day 22 to day 42 and overall (day 0 to day 42). Gain to feed ratio (G:F) was significantly increased (P<0.05) with enzyme supplementation during both starter and grower phases. Enzyme addition increased (P<0.05) serum phosphorus (P) concentration on day 21. On day 42 enzyme supplementation increased (P<0.05) the apparent ileal digestibility of P, dry matter (DM), energy, and N. Addition of a combination of carbohydrases (xylanase and β-glucanase) and phytase to corn–soybean-based diets deficient in ME, CP, Ca and P resulted in a significant increase in growth performance and utilization of P, DM, energy and N in broiler chickens.

Characterization of whole body compositional growth of male ducks during the twenty-nine day post-hatch period

Schinckel, A. P., Einstein, M. E., Ajuwon, K. M. and Adeola, O. 2013. Characterization of whole body compositional growth of male ducks during the twenty-nine day post-hatch period. Can. J. Anim. Sci. 93: 113–122. Changes in whole body dry matter, lipid, ash, energy, crude protein, and amino acids were evaluated during a 29 d post-hatch period in White Pekin ducks. Drakes were assigned to slaughter 1, 8, 15, 22, or 29 d post-hatch with four replicates of four ducks per slaughter period. The body weight (BW) data were fitted to the Weibull function with the form:[Formula: see text]where BWit is the BW of the ith duck at t days of age and A, B, C, and IP are parameters. The value of IP, the inflection point, which minimized the residual SD, was 40 d. Values of A (8591 g, SE=190), B (42.87, SE=11.5), and C (1.7399, SE=0.050) resulted in an R 2 of 0.9836 and residual SD of 83.7 g. Allometric (Y=A BWB), linear-quadratic and exponential (Y=exp (b0+b1BW+b2 (BW)2) functions of BW were fitted to the chemical component and amino acid mass data. Dry matter percentage of the ducks increased (P<0.01) with age. The protein content of the dry matter decreased (P<0.01) from day 1 to day 8 (69 to 58.2%) and then increased to 60% by d 29. Concentrations of several amino acids were affected (P<0.05) by age. The predicted accretion rates of Lys, Trp, and Met relative to protein accretion increased as age increased. The predicted daily accretion rates for major indispensable amino acids increased rapidly the first 5 d post-hatch and subsequently increased but at a decreasing rate to day 29 post-hatch. The relative growth rates of chemical components and indispensable amino acids were affected by age indicating that the nutrient requirements of ducks differ from day 1 to day 29 post-hatch. Compositional growth and amino acid accretion data can be used to model the nutrient requirements of ducks.

Ileal endogenous amino acid losses: response of broiler chickens to fiber and mild coccidial vaccine challenge

The effects of mild coccidial vaccine (5× dose) challenge and fiber levels on ileal endogenous amino acid (EAA) losses was determined in 26-d-old broiler chickens using the regression method. Birds were fed semipurified diets containing 3 levels of casein (40, 80, or 120 g/kg of diet) as the only source of dietary protein at 2 levels of fiber (purified cellulose at 25 or 75 g/kg of diet). One half of the experimental birds were gavaged with coccidial vaccine on d 20. The 3 levels of casein were used to determine EAA losses for each replicate cage of birds. The design of the study was a randomized complete block employing a factorial arrangement of treatments with 2 levels of coccidial challenge (control or unchallenged, and challenged) and 2 levels of fiber, with 6 replicate cages per treatment and 8 birds per cage. Birds were killed on d 26 and contents from the entire ileum were flushed with distilled water and stored at -20°C until processed. Ileal EAA losses were determined from the ordinate intercept, at zero amino acid (AA) intake, of the regression of ileal digesta AA concentration in milligrams per kilogram of DM intake against dietary AA intake in milligrams per kilogram of DM. The effect of fiber level on EAA losses, expressed in milligrams per kilogram of DM intake, were higher (P < 0.05) for most of the AA in birds fed 25 g of fiber/kg of diet. Coccidial vaccine challenge decreased (P < 0.05) EAA losses for 8 of the 18 AA. A significant interaction between fiber level and coccidial vaccine challenge was obtained for all AA except His and Lys. Coccidial vaccine challenge resulted in increased (P < 0.05) NaPi-IIb expression. The results suggest that ileal EAA loss is higher in challenged birds fed the diet containing 25 g of fiber/kg of diet. Changes in EAA losses as a result of dietary fiber level and coccidial infection are important in amino acid nutrition of the broiler chicken.

Regulation of pre-adipocyte proliferation and apoptosis by the small leucine-rich proteoglycans, biglycan and decorin

Evidence for a functional role for extracellular matrix (ECM) proteins in adipose tissue is demonstrated in dynamic changes in expression of ECM genes during adipocyte differentiation and in obesity. Components of the ECM may regulate adipose cell number expansion by restricting pre-adipocyte proliferation, regulating apoptosis and inhibiting adipogenesis. Although pre-adipocytes express multiple proteoglycans, their role in pre-adipocyte proliferation up to now has remained unknown. The study described here was conducted to characterize roles of small leucine-rich proteoglycans (SLRPs) in adipocyte proliferation. Pre-adipocytes were seeded on plates coated with biglycan and decorin and were allowed to differentiate. In addition, pre-adipocytes were incubated on plates coated with biglycan, decorin, or fibronectin and measurements were made of cell proliferation and apoptosis. We are able to report that SLRPs decorin and biglycan did not affect differentiation of our 3T3-L1 cells; however, biglycan and decorin did reduce proliferation of pre-adipocytes, partly by induction of apoptosis. Furthermore, anti-proliferative capabilities of decorin and biglycan were nullified with removal of GAG side-chains suggesting that the chains played key roles in anti-proliferative effects of the SLRPs. We also found that co-treatment of decorin or biglycan with the proteoglycan fibronectin restored normal proliferation, an indication that multiple ECM proteins may act in concert to regulate overall proliferation rates of pre-adipocytes. These studies indicate that SLRPs may compose a regulatory factor in adipose tissue expansion, through hyperplasia.

Adipocytes, myofibers, and cytokine biology: new horizons in the regulation of growth and body composition

Muscle growth in meat animals is a complex process governed by integrated signals emanating from multiple endocrine and immune cells. A generalized phenomenon among meat animal industries is that animals commonly fail to meet their genetic potential for growth in commercial production settings. Therefore, understanding the impact of stress and disease on muscle growth is essential to improving production efficiency. The adipocyte in particular seems to be well positioned as an interface between energy status and immune function, and may thus influence nutrient partitioning and growth through a combination of signals that influence fat metabolism, glucose uptake, and insulin sensitivity. Adipocytes and myofibers are active participants in the innate immune response, and as such, produce a number of metabolic regulators, including leptin, adiponectin, and proinflammatory cytokines. Specifically, adipocytes and muscle cells respond directly to bacterial lipopolysaccharide (LPS) by producing interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNFalpha). However, adipocytes are also the predominant source of the antiinflammatory hormone adiponectin, which regulates the nuclear factor kappa-B transcription factor. The ability to recognize antigens and produce regulatory molecules strategically positions adipocytes and myofibers to regulate growth locally, and to reciprocally regulate metabolism peripherally.

Cloning and expression of porcine adiponectin, and its relationship to adiposity, lipogenesis and the acute phase response

Adiponectin is an adipocyte-derived hormone that has been implicated recently in the regulation of inflammation in immunocytes, and in lipid metabolism and glucose homeostasis in liver, skeletal muscle and adipocytes. However, information in non-rodent models is limited. We have cloned and sequenced the porcine adiponectin open reading frame and evaluated the regulation of adiponectin in vivo following lipopolysaccharide (LPS) or E. coli administration. The porcine sequence shares approximately 88, 86, 85 and 83% homology with the dog, human, cow and mouse adiponectin respectively, and 79-83% similarity with dog, human, cow and mouse proteins at the amino acid level, based on the translated porcine sequence and GenBank submissions for the other species. Relative serum adiponectin concentrations were not altered in pigs infused with E. coli, and mRNA expression in adipose tissue was not responsive to LPS. However, analysis of serum from very lean vs a substantially fatter genotype of pig indicated that relative circulating adiponectin concentrations are higher (P<0.01) in the lean pigs than in the fatter genotype, and that the difference is established relatively early in the growth curve. Also, incubating pig adipocytes for 6 h with recombinant pig adiponectin resulted in an approximately 30% reduction (P<0.05) in lipogenesis compared with adipocytes under basal conditions and with those incubated in the presence of insulin. This is the first report in any species that adiponectin antagonizes the incorporation of glucose carbon into lipid in the adipocyte, and provides additional evidence that adiponectin acts as an autocrine regulatory factor to regulate energy metabolism.