Marginal deficiencies of dietary arginine and methionine could suppress growth performance and immunological responses in broiler chickens

The present study was conducted to investigate the effects of different levels of dietary arginine (Arg) and methionine (Met) on performance, immune responses, and carcass characteristics of broiler chickens. A total of 540 day‐old Ross 308 broiler chicks were randomly assigned into the nine experimental diets, consisting five replicates of 12 birds each. Dietary treatments included three different levels (90%, 100%, and 110% of National Research Council [NRC] specifications) of either dietary Arg or Met, which were fed to the birds according to a 3 × 3 factorial arrangement of treatments during a 42 days feeding trial. Results showed that supplementation of Arg and Met into the deficient‐diets increased (p < .01) weight gains during all trial periods. Although average daily feed intake (ADFI) was not influenced by dietary treatments, increasing Arg up to 100% of NRC recommendations improved (p < .05) feed conversion ratio (FCR) throughout the trial period. Similarly, supplementation of deficient‐diets with Met improved FCR values. There was a significant (p < .01) Arg × Met interaction for ADFI during the starter period; increasing the dietary Arg level increased ADFI when the diets were deficient in Met, while had an opposite effect in diets containing higher dietary Met levels. On the other hand, dietary Met fortification improved (p = .067) FCR values to a greater extent in 110% Arg‐diets during the entire trial period. Although different levels of Arg and Met had no marked effects on carcass yield and abdominal fat percentage, supplemental Arg up to 100% of NRC values increased (p < .01) the relative weights of spleen and bursa of Fabricius. Furthermore, bursa weight was affected by Arg × Met interaction (p < .01), so that supplemental Arg level of 100% of NRC increased the relative bursa weight in birds that were fed diets containing 90% and 110% of Met. Serum uric acid level was decreased (p < .05) as a result of dietary Arg fortification up to 110% of NRC recommended values. Supplementation of deficient‐diets with Met decreased (p < .05) serum cholesterol level. Although Newcastle antibody titer was not affected by dietary Arg or Met levels, Arg fortification of deficient‐diets increased (p < .001) antibody responses against infectious bronchitis (IBV) and bursal (IBD) disease viruses. Similarly, Met supplementation of deficient‐diets increased IBD antibody titer. There were significant (p < .05) Arg × Met interactions for IBV and IBD titers; Met fortification of 110% Arg‐diets was more effective in increasing antibody titers. An increase in dietary Met level up to 100% of NRC values increased (p < .001) serum concentration of γ‐globulins. The present findings imply that supplemental Arg could affect feed efficiency and antibody responses when the diets were already fortified with a sufficient Met level.     

Effects of different dl‐selenomethionine and sodium selenite levels on growth performance,immune functions and serum thyroid hormones concentrations in broilers

This trial was conducted in a 2 × 3 + 1 factorial arrangement based on a completely randomized design to evaluate the effects of different dl ‐selenomethionine (dl ‐Se‐Met) and sodium selenite (SS) levels on growth performance, immune functions and serum thyroid hormones concentrations in broilers. A total of 840 Ross 308 broilers (7 days old) were allocated by body weight to seven treatments (three replicates of 40 birds each treatment) including (1) basal diet (containing 0.04 mg of selenium (Se)/kg; control) without supplementary Se; (2, 3 and 4) basal diet + 0.05, 0.15 or 0.25 mg/kg Se as SS; (5, 6 and 7) basal diet + 0.05, 0.15 or 0.25 mg/kg Se as dl ‐Se‐Met. The experiment lasted 42 days. The results revealed that dietary Se supplementation improved (p < 0.05) average daily gain, feed efficiency, immune organ index, serum immunoglobulin A (IgA), immunoglobulin G (IgG), immunoglobulin M (IgM) and triiodothyronine (T₃) concentrations and decreased (p < 0.01) thyroxine (T₄)/T₃ ratio in serum compared with the control. Broilers receiving the dl ‐Se‐Met‐supplemented diets had higher (p < 0.05) feed efficiency, thymus index, the amounts of IgA, IgG, IgM and T₃ as well as lower (p < 0.05) serum T₄ concentrations and T₄/T₃ ratio than those consuming the SS‐supplemented diets. Serum IgA and IgM levels of broilers fed 0.15 mg Se/kg were significantly higher (p < 0.05) than those of broilers fed 0.05 or 0.25 mg Se/kg. In summary, we concluded that dl ‐Se‐Met is more effective than SS in increasing immunity and promoting conversion of T₄ to T₃, thus providing an effective way to improve the growth performance of broilers. Besides, based on a consideration of all experiment indices, 0.15 mg Se/kg was suggested to be the optimal level of Se supplementation under the conditions of this study.     

Effects of chestnut tannins on intestinal morphology,barrier function,pro‐inflammatory cytokine expression,microflora and antioxidant capacity in heat‐stressed broilers

A study was conducted to evaluate the effects of chestnut tannins (CT) on intestinal morphology, barrier function, pro‐inflammatory cytokine expression, microflora and antioxidant capacity in heat‐stressed broilers. Four hundred 28‐day‐old male Ross 308 broilers were randomly assigned into four groups, with 10 replicates per group and 10 broilers per replicate. The broilers in the normal (NOR) group were kept at 22 ± 1°C and fed the basal diet, and each of the other three groups were treated with cyclic heat (33 ± 1°C from 0800 to 1800 and 22 ± 1°C from 1800 to 0800) and fed the basal diet with 0 (HT), 1 (CT1) or 2 (CT2) g of CT/kg of diet. The experiment lasted for 14 days. Compared with the HT group, broilers in the NOR and CT2 groups had higher (p < .05) average daily gain and villus height in the jejunum and lower serum d ‐lactate (p < .001) and diamine oxidase (p < .01) levels. The addition of 2 g CT/kg of diet increased the total antioxidant capacity (p < .001) and superoxide dismutase activities (p < .05) and zonula occludens‐1 mRNA expression level (p < .05) and decreased the malondialdehyde concentration (p < .01) and mRNA expression levels of interleukin‐6 (p < .001) and nuclear factor kappa B (p < .001) in the jejunal mucosa of heat‐stressed broilers. The populations of Escherichia coli and Clostridium in the jejunum (p < .01) and caecum (p < .05) of broilers in the HT group were higher than those in the NOR and CT2 groups. In conclusion, the addition of 2 g CT/kg of diet seemed to be a feasible means of alleviating the negative effects of heat stress on the growth performance and intestinal function of broilers.     

Effects of Astragalus membranaceus,Codonopsis pilosula and allicin mixture on growth performance,nutrient digestibility,faecal microbial shedding,immune response and meat quality in finishing pigs

A 12‐week trial with 120 [(Landrace×Yorkshire)×Duroc] pigs (45.65 ± 1.93 kg) was conducted to evaluate the effects of Astragalus membranaceus, Codonopsis pilosula and allicin mixture (HM) supplementation on growth performance, nutrient digestibility, faecal microbial shedding, immune response and meat quality in finishing pigs. Pigs were allocated to one of three treatments with 0, 0.025% (HM1) and 0.05% (HM2) HM supplementation in a randomized complete block design according to sex and BW. Each treatment contained 10 replications with four pigs (two barrows and two gilts) per pen. Dietary HM resulted in a higher G:F (p < 0.05) than CON group during weeks 7 to 12 and the overall periods. Pigs fed HM2 diet had higher ADG than pigs fed CON diet. Pigs fed HM2 supplementation diet led to a higher (p < 0.05) apparent total tract digestibility (ATTD) of dry matter (DM) and gross energy (GE) than pigs fed CON diet at week 6, while the supplementation of HM led to a higher (p < 0.05) ATTD of DM and GE than pigs fed CON diet at week 12. The faecal E. coli counts were reduced, and Lactobacillus counts were increased by increasing HM supplementation (p < 0.05). Pigs fed HM1 diet had higher (p < 0.05) WBC concentration than those fed CON and HM2 diets at week 6. Pigs fed HM‐supplemented diet had higher (p < 0.05) IgG and IgA concentrations than those fed CON diet at week 12. Pigs fed HM diet noted better (p < 0.05) meat colour and redness value than pigs fed CON diet. Pig fed HM2 reduced (p < 0.05) the lightness value compared with CON group. In conclusion, dietary HM supplementation exerted beneficial effects on growth performance, nutrient digestibility, intestinal microbial balance (increased Lactobacillus counts and decreased E. coli counts), immune response and meat quality.     

Influence of Bacillus subtilis GCB‐13‐001 on growth performance,nutrient digestibility,blood characteristics,faecal microbiota and faecal score in weanling pigs

The present study investigated the influence of Bacillus subtilis GCB‐13‐001 on growth performance, nutrient digestibility, blood characteristics, faecal microbiota and faecal score in weanling pigs. A total of 120 weaning pigs [(Landrace × Yorkshire) × Duroc; 7.73 ± 0.75 kg (28 days of age)] were randomly allotted into three treatments according to their initial body weight (BW) and gender in a 6‐week experiment. There were 8 replication pens in each treatment, with five pigs/pen. Dietary treatment groups were as follows: (a) basal diet (CON), (b) CON + 0.1% Bacillus subtilis GCB‐13‐001 1 × 10⁸ CFU/kg (T1) and (c) CON + 0.1% Bacillus subtilis GCB‐13‐001 1 × 10⁹ CFU/kg (T2). Days 1 to 7, the BW and ADG with T2 treatment were higher (p < .05) than CON treatment, as well as F:G showed trends in linear reduction (p < .1). Days 8 to 21, the BW and ADG were improved (p < .05) in pigs offered T1 and T2 diets compared with CON diet. Days 22 to 42, BW and ADG were higher (p < .05) in pigs fed T2 diet than CON and T1 diets, and the pigs fed T1 diet had higher BW than CON treatment. Overall, the ADG with the T2 treatment was higher (p < .05) than that with the T1 and CON treatments, and pigs offered T1 treatment had higher (p < .05) ADG than CON treatment. Moreover, F:G ratio were significantly decreased (p < .05) by T2 treatment compared with CON treatment. The faecal Lactobacillus counts were improved, and E. coli counts were reduced (p < .05) in pigs fed T2 diet compared with CON at the end of the experiment. In conclusion, supplementation of 0.1% Bacillus subtilis GCB‐13‐001 1 × 10⁹ CFU/kg has shown a beneficial effect in improving BW, increase ADG, decrease F:G ratio.     

Independent and combined effects of Satureja khuzistanica essential oils and acetic acid on prevalence and intensity of fatty liver syndrome in broiler chickens

Two hundred fifty two male Ross 308 broiler chicks were raised to examine the effects of Satureja khuzistanica essential oils (SkEO; 0, 200, 300, 400, 500 and 600 mg/bird/day) administrated via oral gavage and dietary supplementation of acetic acid (AA; 0 or 20 g/kg) in a 6 × 2 factorial fashion using a complete randomized block design with seven replicates of three birds each. In Day 34 of age, liver fat percentage decreased by increasing SkEO levels in a quadratic trend (p < .05). Oral gavag of 200 and 300 mg of SkEO decreased AST activity by 16.67% and 16.94%, respectively, compared with the control birds (p < .05). In Day 38 of age, liver percentage was greater by 0.37% in the birds received 400 mg SkEO than those given 500 mg (p < .05). Liver fat percentage decreased in the birds fed the acidified diet and received 300 and 500 mg SkEO as well as in the birds offered 200 and 400 mg of SkEO and fed non-acidified diet than those received acidified diet with no SkEO administration (p < .05). Prevalence of score zero for hepatocytic vacuolations and necrosis was 80.00% and 42.42% in the birds receiving 600 mg SkEO respectively. Median for relative frequency of scores for hepatocytic vacuolations and hepatocytic necrosis was lesser in the birds received SkEO by oral gavage compared with that of control birds (p < .05). In conclusion, administration of SkEO via oral gavage reduced liver fat in broiler chicken but no consistent dosage could be verified as the effective dosage for all ages concerned. The acidified diet per se showed no evident effect on liver fat at all ages considered. The SkEO × AA interaction exhibited promising but unreliable effects on liver colour score in market age (42 days).     

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.     

Effects of multistrain probiotics on growth performance,nutrient digestibility,blood profiles,faecal microbial shedding,faecal score and noxious gas emission in weaning pigs

This experiment was conducted to investigate the efficacy of multistrain probiotics in weaning pigs. A total of 125 28‐day‐old weaning pigs [(Landrace × Yorkshire) × Duroc] with an initial average body weight (BW) of 7.26 ± 0.76 kg were randomly allotted into 5 treatments, 5 replicate pens/treatment with 5 pigs/pen for 42‐day experiment. Dietary treatments were as follows: CON, basal diet; PC1, CON + 0.01% multistrain probiotics; PC2, CON + 0.03% multistrain probiotics; PC3, CON + 0.06% multistrain probiotics; PC4, CON + 0.1% multistrain probiotics. On day 14, pigs fed the PC4 diet had higher BW gain than pigs fed the CON diet. On day 42, pigs fed multistrain probiotics supplementation diets had higher BW gain than pigs fed the CON diet. From days 1 to 14, pigs fed the PC2, PC3 and PC4 diets had higher (p < 0.05) ADG than pigs fed the CON diet. From day 15 to 42, pigs fed the multistrain probiotics supplementation diets had higher (p < 0.05) average daily gain (ADG) and gain: feed ratio (G:F) than pigs fed the CON diet. In the overall period, pigs fed the multistrain probiotics supplementation diets had higher (p < 0.05) ADG and pigs fed the PC2 and PC4 diets had higher (p < 0.05) G:F than pigs fed the CON diet. On day 42, pigs fed the PC4 diet had higher (p < 0.05) apparent total tract digestibility (ATTD) of dry matter (DM), nitrogen (N) and gross energy (GE), faecal Lactobacillus counts and lower (p < 0.05) E. coli counts and NH₃ emission than pigs fed the CON diet. Pigs fed the multistrain probiotics supplementation diets had lower (p < 0.05) H₂S and total mercaptans emissions than pigs fed the CON diet. Conclusions, dietary supplementation with 0.1% probiotics improved growth performance, nutrition digestibility and intestinal microflora balance and decreased faecal noxious gas emissions in weaning pigs.     

Effect of dietary polyphenol‐rich grape seed on growth performance,antioxidant capacity and ileal microflora in broiler chicks

In this study, we examined the effect of dietary supplementation with grape seed (GS) on the performance, carcass traits, plasma biochemistry, antioxidant status and ileal microflora in broilers. Experiment diets included a control diet (without additive) and three levels of GS powder (10, 20 and 40 g/kg of diet). Each diet was fed to a total of 300 one‐day‐old Cobb‐500 chicks for 42 days. The addition of 20 g/kg of GS to the basal diet increased final body weight and body weight gain, improved the feed conversion ratio and did not affect feed intake. Dietary 20 g GS significantly increased (p < .05) the percentage of carcass yield %, dressing % and gizzard. However, the addition of 40 g/kg of GS significantly reduced the percentage of abdominal fat in the birds. Diets supplemented with GS showed the lowest content of ether extract compared with the control group (p < .05). The physical characteristics of meat and the chemical composition of DM, CP and ash were not significantly influenced by treatments. In the GS groups, plasma protein, albumin, globulin, aspartate aminotransferase and alanine aminotransferase concentrations showed no significant change compared with the control group. Broilers fed a diet supplemented with GS had lower levels of plasma glucose, total lipids, triglycerides and cholesterol compared with the control birds (p < .05). The addition of 40 g of GS significantly (p < .05) enhanced the activity of reduced glutathione, catalase, superoxide dismutase, glutathione peroxidase and GST, and correlated with significantly decreased thiobarbituric acid‐reactive substances levels compared with the control group. The value of ileal pH was not significantly affected by the GS levels. Broilers fed diets supplemented with GS had lower ileal Streptococcus spp. and Escherichia coli populations but higher Lactobacillus spp. populations (p < .05). No adverse effects on birds’ health were detected due to the use of GS. Thus, GS could be recommended as an herbal supplement in the diet of broiler chickens to improve performance, reduce blood lipids, enhance antioxidant capacity and decrease detrimental bacteria in the ileum.     

Application of the slope‐ratio growth assay technique to estimate tryptophan availability in soybean meal fed to young rats

The slope‐ratio assay for rat was used to determine whether tryptophan (Trp) availability in soybean meal (SBM) is affected by the presence of other amino acids (AAs). In a preliminary study, rats were fed graded levels of Trp‐supplemented diets to establish the Trp concentration range over which the weight gain response was linear. This range was found to be from 0.04% to 0.12% Trp. Subsequently, rats were fed basal (0.045% Trp) or Trp‐supplemented diets from three different sources: l ‐Trp alone, SBM, or l ‐Trp mixed with other AAs to reflect AA levels in the test SBM (AA‐mix). Weight gain in rats increased linearly with supplemental Trp intake (p < .05) for all Trp sources. Compared to the slope achieved with l ‐Trp alone, the estimated availability of Trp in SBM was 84.4%, while for the AA‐mix it was 93.4%. It is evident that the 6.6% reduction in l ‐Trp availability in AA‐mix is due to metabolic costs derived from excess levels of other AAs beside Trp, given that the absorption of crystalline l ‐Trp in the small intestine is 100%. In conclusion, the Trp availability of SBM was estimated to be around 90.4% (i.e., 84.4/93.4 × 100) after correcting for the effects of the other AAs in SBM.     

Supplemental methionine sources have a neutral impact on oxidative status in broiler chickens

To determine the effect of different dietary Met sources on oxidative status, male Cobb 500 broiler chickens were fed from day of hatch to 26 days of age (d26) a diet deficient in sulfur amino acids (control) or a diet containing 0.22% DL‐Met, 0.22% L‐Met or 0.31% Met precursor, DL‐2‐hydroxy‐4‐(methylthio) butanoic acid (DL‐HMTBA) to meet the Met + Cys requirements. Liver, breast muscle, duodenum, jejunum, and ileum were collected at day 10 (d10) and d26 to assay markers of oxidative stress, including total glutathione (TGSH), oxidized glutathione (GSSG), reduced glutathione (rGSH), protein carbonyls, thiobarbituric acid reactive substances (TBARS) and ferric reducing/antioxidant power (FRAP). In breast muscle, TGSH and rGSH were greater in L‐Met and DL‐HMTBA groups than in the control group (p < 0.05). An interaction of treatment and age was observed for TGSH in ileum (p = 0.01) and jejunum (p = 0.01), for GSSG in jejunum (p < 0.001), and for rGSH in ileum (p = 0.02). The ratios of rGSH to GSSG and GSSG to TGSH, which define oxidative status, were not affected by Met source. Protein carbonyls varied among groups in jejunum (p = 0.05) and breast muscle (p < 0.001), but were in the normal physiological range. No difference among treatment groups was observed for TBARS and FRAP in different tissues. Age effects were observed in all tissues for multiple oxidative stress markers. In conclusion, consuming different sources of supplementary Met did not alter the oxidative status in several tissues of broilers. Met + Cys deficiency did not compromise antioxidant capacity of chickens although growth was retarded.     

Effects of supplementing broiler diets with coriander seed powder on growth performance,blood haematology,ileum microflora and economic efficiency

A total of 480 one‐day‐old Arbor Acres broiler chicks were randomly assigned to four dietary groups, each including six replicates (n = 20/replicate). Broilers in the first group (G1) were fed a basal diet without any additives (control). Broilers in groups 2, 3 and 4 (G2, G3 and G4) were fed a basal diet supplemented with 0.1%, 0.2% and 0.4% coriander (Coriandrum sativum L.) seed powder (CSP) respectively. Feeding trials lasted for 42 days, and after that growth, carcass traits, haematological parameters, gut microbiota and economic efficiency (EE) were evaluated. Final body weight (FBW), total weight gain (TWG), total feed intake (TFI) and red blood cell (RBC) counts of broilers in the G4 and G3 treatment groups were significantly higher (p < .05) compared with broilers in the G1 treatment group. The feed conversion ratio (FCR) was better (p < .05) in the G4 treatment group (1.72) than in the G1 treatment group (1.84). Broilers in CSP treatment groups had significantly higher haemoglobin (Hb) concentrations, packed cell volume (PCV) and platelet counts, and had lower (p < .05) Escherichia coli and Clostridium perfringens counts compared with broilers in the G1 treatment group. Dressing, liver, pancreas, bursa and thymus percentages were higher (p < .05) in broilers in the G4 (70.30, 3.18, 0.31, 0.10 and 0.32% respectively) treatment group, compared with broilers in the control (G1) group (66.57, 2.37, 0.23, 0.04 and 0.21% respectively). Broilers in treatment groups G4 and G3 had lower percentages of abdominal fat and lower total bacterial counts (p < .05) than broilers in treatment groups G2 and G1. The highest economic efficiency (EE) was found in treatment group G4, and EE in this group was 13.06% greater than in the control (G1) group.     

Reduced dietary protein level influences the free amino acid and gene expression profiles of selected amino acid transceptors in skeletal muscle of growing pigs

This study was conducted to evaluate the effect of reduced dietary protein level on growth performance, muscle mass weight, free amino acids (FAA) and gene expression profile of selected amino acid transceptors in different fibre type of skeletal muscle tissues (longissimus dorsi, psoas major, biceps femoris) of growing pigs. A total of 18 cross‐bred growing pigs (Large White × Landrace × Duroc) with initial body weight (9.57 ± 0.67 kg) were assigned into three dietary treatments: 20% crude protein (CP) diet (normal recommended, NP), 17% CP diet (low protein, LP) and 14% CP diet (very low protein, VLP). The results indicated improved feed‐to‐gain ratio was obtained for pigs fed LP and NP diets (p < 0.01), while the pigs fed VLP diet showed the worst growth performance (p < 0.01). There was no significant difference in the weights of longissimus dorsi and psoas major muscle between LP and NP groups (p > 0.05). Majority of the determined FAA concentration of LP group were greater than or equal to those of NP group in both longissimus dorsi and psoas major muscle (p < 0.01). Further, the mRNA expression levels of sodium‐coupled neutral amino acid transceptor 2, L‐type amino acid transceptor 1 and proton‐assisted amino acid transceptors 2 were higher in skeletal muscle tissue in LP group compared to those of the pigs fed NP or VLP diet. These results suggested that reduced dietary protein level (3 points of percentage less than recommended level) would upregulate the mRNA expression of amino acid transceptors to enhance the absorption of FAA in skeletal muscle of growing pigs. There seems to be a relationship between response of AA transceptors to the dietary protein level in skeletal muscle tissue of different fibre type. To illustrate the underlying mechanisms will be beneficial to animal nutrition.     

Reduced fasting periods increase intestinal permeability in chickens

Fasting of up to 24 hr has been shown to increase intestinal permeability (IP) in chickens. The aim of this study was to determine whether fasting duration of 4.5 and 9 hr increased IP and whether l ‐glutamine (a non‐essential amino acid) supplementation before fasting provided some protection of barrier function as shown in other species. Ross 308 male broilers (n = 96) were fed either a control diet or the same diet supplemented with 1% glutamine from d0 to d38 post‐hatch. On d37, the birds were assigned to single‐bird metabolism cages and were fasted for either 0, 4.5, 9 or 19.5 hr. This study design was 2 × 4 factorial with two levels of glutamine and four levels of fasting. Birds in the 0‐hr fasting group had free access to feed. All birds had ad libitum access to water. To measure IP on day 38, following their respective fasting periods, birds were administered two separate oral gavages of fluorescein isothiocyanate dextran (FITC‐d) followed by lactulose, mannitol and rhamnose (LMR) sugars, 60 min apart. Whole blood was collected from the jugular vein 90 min post‐LMR sugar gavage. FITC‐d and L/M/R ratios were measured by spectrophotometry and high‐performance ionic chromatography respectively. Lipopolysaccharide (LPS) endotoxins in plasma of the birds fed the control diet were also measured using chicken‐specific LPS antibody ELISA. Serum FITC‐d and plasma L/M and L/R ratios for 4.5, 9 and 19.5 hr were significantly (p < .05) higher compared to the non‐fasting group. However, IP was not different in the glutamine‐supplemented group (p > .05) compared to the control group. LPS concentrations measured by the ELISA were below the detectable range. We conclude that fasting periods of 4.5 and 9 hr increased IP compared to non‐fasted birds and dietary glutamine supplementation did not ameliorate changes in IP.     

Effects of dietary betaine on growth performance,fat deposition and serum lipids in broilers subjected to chronic heat stress

We evaluated the effects of supplementing betaine on growth performance, fat deposition and lipid metabolism status in broilers kept under chronic heat stress. Five hundred and forty chicks were randomly divided into six groups and the two normal temperature groups were held at normal ambient temperature and fed the basal diet (CONT) and basal diet plus 0.1% betaine, respectively. Heat stressed (HS) broilers were held at 32 ± 1°C from days 22 to 42 and fed the basal diet containing variable levels of betaine. Broilers were examined at days 28, 35 and 42 for body weight, feed consumption, fat deposition and serum lipids. The CONT and betaine‐supplemented groups showed higher (P < 0.01 or P < 0.05) feed consumption, body weight gain, and lower feed : gain ratio compared with the HS‐CONT group. Meanwhile, heat stress increased abdominal, intermuscular and subcutaneous fat deposition, whereas the supplemental betaine significantly decreased those compared with the HS‐CONT group. Additionally, betaine supplementation significantly decreased triglyceride, free fatty acids, low‐density lipoprotein cholesterol and high‐density lipoprotein cholesterol compared with HS‐CONT. Chronic HS reduces broiler production performance. However, betaine can reverse these negative effects partially and thus improve carcass composition by changing lipid metabolism.     

Carcass yields,muscle amino acid and fatty acid profiles,and antioxidant indices of broilers supplemented with synbiotic and/or organic acids

The objective of the current research was to explore the possible impacts of dietary supplementation with synbiotic and/or organic acids (OA) on the performance traits, carcass yields and muscle amino acid and fatty acid (FA) profiles of broilers. Randomly, a total of 160 day‐old chicks (Ross 308) were assigned into four equal groups (40 birds each), with each group subdivided into eight replicates (five birds/pen). The control group (CON) fed the basal diet with no supplements, while diets of the treated groups were supplemented with OA (Sodium butyrate 40%; 1 g/kg), synbiotic (comprised Bacillus subtilis, Saccharomyces cerivisiae, Streptococcus faecium, Mannan‐Oligosaccharides and β‐Glucan; 1 g/kg) and equal mix of OA and synbiotic (2 g/kg). Broilers fed the diets supplemented with synbiotic or synbiotic plus OA produced a significantly higher feed utilization efficiency (p = 0.021) and carcass yields (p = 0.038) than the CON and OA‐supplemented groups. The group fed the diet supplemented with the synbiotic showed lowered serum cholesterol (p = 0.049), triglycerides (p = 0.001) and very low density lipoprotein (p = 0.032) when compared with the CON group. Regarding the polyunsaturated FA (PUFA) of breast muscles, synbiotic‐supplemented birds had significantly lower n‐6:n‐3 ratio (p = 0.047), however, a greater hypocholesterolaemic to hypercholesterolaemic FA (H/H) ratio was reported when compared with the CON group (p = 0.002). Among the essential amino acids, the contents of leucine and methionine in the breast (p = 0.032 and 0.007 respectively) and thigh (p = 0.023 and 0.003 respectively) muscles were greater in the synbiotic‐supplemented birds compared with the CON group. In conclusion, the synbiotic‐supplemented diet improved the PUFA:SFA, n‐6:n‐3 and H/H ratios by altering the FA composition of broiler muscles, which are important with regards to human health.     

Dietary levels of protein and free amino acids affect pancreatic proteases activities,amino acids transporters expression and serum amino acid concentrations in starter pigs

The dietary contents of crude protein and free amino acids (AA) may affect the protein digestion and AA absorption in pigs. Trypsin and chymotrypsin activities, AA serum concentrations and expression of AA transporters in the small intestine of pigs fed a low protein, AA‐supplemented (19.2%, LPAA) or a high protein (28.1%, HP), wheat‐soybean meal diet were measured in two 14‐d trials. The LPAA diet contained free L‐Lys, L‐Thr, DL‐Met, L‐Leu, L‐Ile, L‐Val, L‐His, L‐Trp and L‐Phe. All pigs were fed the same amount of feed (890 and 800 g/d for trial 1 and 2 respectively). In trial 1, samples of mucosa (duodenum, jejunum and ileum) and digesta (duodenum and jejunum) were collected from 14 pigs (17.2 ± 0.4 kg); in trial 2, blood samples were collected from 12 pigs (12.7 ± 0.3 kg). The trypsin and chymotrypsin activities in both intestinal segments were higher in pigs fed the HP diet (p < 0.01). Trypsin activity was higher in jejunum than in duodenum regardless the dietary treatment (p < 0.05). Pigs fed the LPAA diet expressed more b^0,+AT in duodenum, B⁰AT1 in ileum (p < 0.05), and tended to express more y⁺LAT1 in duodenum (p = 0.10). In pigs fed the LPAA diet, the expression of b^0,+AT was higher in duodenum than in jejunum and ileum (p < 0.01), but no difference was observed in pigs fed the HP diet. Ileum had the lowest b^0,+AT expression regardless the diet. The serum concentrations of Lys, Thr and Met were higher in LPAA pigs while serum Arg was higher in HP pigs (p < 0.05). Serum concentrations of AA appear to reflect the AA absorption. In conclusion, these data indicate that the dietary protein contents affect the extent of protein digestion and that supplemental free AA may influence the intestinal site of AA release and absorption, which may impact their availability for growth of young pigs.     

Effect of probiotic supplementation on growth performance,intestinal morphology,barrier integrity,and inflammatory response in broilers subjected to cyclic heat stress

This study investigated the protective effects of probiotic on heat stress‐induced intestinal injury and inflammatory response in broilers. A total of 180 male broilers were randomly allocated to three treatments with four replicates each from 22 to 42 days of age. The broilers were either raised under thermoneutral (TN) conditions (23 ± 1°C) or subjected to cyclic heat stress (28–35–28°C for 12 hr daily). The broilers kept at TN conditions were fed a basal diet, and those exposed to heat stress were fed basal diets supplemented with or without probiotic at a dose of 1.5 × 10⁸ cfu/kg. Compared with the TN group, heat stress decreased (p < .05) the growth performance, reduced (p < .05) villus height and villus height: crypt depth ratio in intestinal mucosa, increased (p < .05) serum levels of D‐lactic acid on day 28 and endotoxin, TNF‐α and IL‐6 on day 42, and decreased (p < .05) serum IL‐10 content on day 42. Dietary supplementation of probiotic reversed (p < .05) all these changes except for the growth performance in heat‐stressed broilers. In conclusion, dietary inclusion of probiotic could improve intestinal morphology and barrier function, alleviate inflammatory response, but exert no ameliorative effect on growth performance of broilers under cyclic heat stress.     

Effects of lactulose supplementation on performance,blood profiles,excreta microbial shedding of Lactobacillus and Escherichia coli,relative organ weight and excreta noxious gas contents in broilers

This study was to evaluate the effects of lactulose supplementation on performance, blood profiles, excreta microbial shedding of Lactobacillus and Escherichia coli, relative organ weight and excreta noxious gas contents in broilers. A total of 720 ROSS 308 broilers with a body weight of 46 ± 0.1 g (1 day of age) were used in a 28‐d experiment. Broilers were randomly allotted to 4 experiment diets with 12 replicate pens and 15 birds per pen. Dietary treatments were as follows: NC, negative control (without antibiotic); PC, NC + 0.1% tiamulin; L1, NC + 0.1% lactulose; and L2, NC + 0.2% lactulose. Broilers were fed with phase 1 (1–8 day), phase 2 (9–18 day) and phase 3 (19–28 day) diets in the form of mash. During day 1–8, broilers fed the PC and L2 diets had higher (p < 0.05) body weight gain than those fed the NC diet. During day 19–28, broilers fed the L1 and L2 diets had lower (p < 0.05) feed intake than those fed the NC diet. The feed conversion ratio (FCR) was decreased (p < 0.05) in L1 treatment compared with NC treatment. Overall, the FCR was improved (p < 0.05) in all supplementation treatments compared with NC treatment. The apparently metabolizable nitrogen in L1 treatment was higher (p < 0.05) than that in NC treatment at day 28. The excreta Lactobacillus was increased and E. coli was decreased in PC and L2 treatments compared with NC treatment at day 28 (p < 0.05). The excreta NH₃, H₂S and acetic acid contents were decreased (p < 0.05) in L1 and L2 treatments compared with NC treatment. The relative weight of abdominal fat of broilers fed the PC diet was lowest (p < 0.05) compared with other treatments. In conclusion, this study indicated that dietary supplementation of 0.1% or 0.2% lactulose could improve growth performance, decrease excreta E. coli and excreta NH₃ and H₂S contents.     

Leucine alone or in combination with glutamic acid,but not with arginine,increases biceps femoris muscle and alters muscle AA transport and concentrations in fattening pigs

Forty‐eight Duroc × Large White × Landrace pigs with an average initial body weight of 77.09 ± 1.37 kg were used to investigate the effects of combination of leucine (Leu) with arginine (Arg) or glutamic acid (Glu) on muscle growth, free amino acid profiles, expression levels of amino acid transporters and growth‐related genes in skeletal muscle. The animals were randomly assigned to one of the four treatment groups (12 pigs/group, castrated male:female = 1:1). The pigs in the control group were fed a basal diet (13% Crude Protein), and those in the experimental groups were fed the basal diet supplemented with 1.00% Leu (L group), 1.00% Leu + 1.00% Arg (LA group) or 1.00% Leu + 1.00% Glu (LG group). The experiment lasted for 60 days. Results showed an increase (p < 0.05) in biceps femoris (BF) muscle weight in the L group and LG group relative to the basal diet group. In longissimus dorsi (LD) muscle, Lys, taurine and total essential amino acid concentration increased in the LG group relative to the basal diet group (p < 0.05). In LG group, Glu and carnosine concentrations increased (p < 0.05) in the BF muscle, when compared to the basal diet group. The Leu and Lys concentrations of BF muscle were lower in the LA group than that in the L group (p < 0.05). A positive association was found between BF muscle weight and Leu concentration (p < 0.05). The LG group presented higher (p < 0.05) mRNA levels of ASCT2, LAT1, PAT2, SANT2 and TAT1 in LD muscle than those in the basal diet group. The mRNA levels of PAT2 and MyoD in BF muscle were upregulated (p < 0.05) in the LG group, compared with those in the basal diet group. In conclusion, Leu alone or in combination with Glu is benefit for biceps femoris muscle growth in fattening pig.