Effects of chitooligosaccharide supplementation on growth performance, nutrient digestibility, blood characteristics and immune responses after lipopolysaccharide challenge in weanling pigs

The objective of this study was to determine the effects of dietary supplementation with chitooligosaccharide (COS) on growth performance, nutrient digestibility, blood characteristics and immune response in lipopolysaccharide-challenged weanling pigs. A total of 90 crossbred weanling pigs (5.44 ± 0.50 kg BW) were employed in Exp. 1. The three dietary treatments were basal diets supplemented with 0, 2.5, and 5 g COS/kg, and fed for 28 d. Each treatment had 6 replications with 5 pigs per pen. Increasing the level of supplemental COS tended to linearly (P < 0.10) improve ADG and ADFI during phase 2 and overall period, while there were no differences in G:F. The linear improvement in the apparent DM (P < 0.05) and N (P < 0.10) digestibility in pigs fed COS supplemented diets was noticed. The tested blood characteristics were not influenced under non-challenge conditions. In Exp. 2, a total of 20 pigs (5.22 ± 0.31 kg BW) were initially assigned to two dietary treatments and fed basal diets supplemented with 0 or 0.5 g COS/kg for 28 d. At the end of d 28, half of the pigs in each treatment (n = 5) were injected i.p. with Escherichia coli lipopolysaccharide at a concentration of 100 μg/kg of BW. The other half of the pigs in each treatment were injected with sterile saline solution at a concentration of 100 μg/kg of BW. This arrangement resulted in a 2 × 2 factorial design with diet and LPS challenge as the main effects. Blood sample and rectal temperature data were collected at 0, 2, 4 and 12 h post-challenge. Rectal temperatures increased as the result of LPS injection at 4 and 12 h post-challenge (P < 0.05). Serum cortisol, IGF-1, and TNF-α concentration were also increased as the result of LPS challenge (P < 0.05). The COS treatments resulted in lower cortisol concentrations at 2 h and higher IGF-1 concentrations at 4 h post-challenge (P < 0.05). COS and LPS interactions were also observed on cortisol and IGF-1 when the COS effects were presented (P < 0.05). Haptoglobin concentrations remained unaffected throughout the challenge period. White blood cell counts were increased in the LPS-treated pigs at 2 and 4 h post-challenge (P < 0.01). Lymphocyte count was elevated at 2 h and reduced at 12 h post-challenge as the result of LPS challenge (P < 0.05). However, there were no COS main effects observed on lymphocyte count throughout the challenge period. The comparison between two LPS challenged treatments also indicated that COS treatment has beneficial effects on rectal temperature, cortisol and IGF-1 concentrations. In conclusion, dietary supplementation with COS had little effect on nutrient digestibility and inflammatory stress markers in weanling pigs.     

Effects of berberine on the growth performance,antioxidative capacity and immune response to lipopolysaccharide challenge in broilers

This study evaluated the effects of berberine on growth performance, immunity, haematological parameters, antioxidant capacity, and the expression of immune response‐related genes in lipopolysaccharide (LPS)‐challenged broilers. We assigned 120 one‐day‐old male broilers (Ross 308) to two treatment groups; each group included two subgroups, each of which included six replicates of five birds per replicate. The experiment used a 2 × 2 factorial arrangement with berberine treatment (0 or 60 mg/kg dietary) and challenge status [injection of saline (9 g/L w/v) or LPS (1.5 mg/kg body weight)] as the main factors. On days 14, 16, 18 and 20, broilers were intraperitoneally injected with LPS or physiological saline. Blood and liver samples were collected on day 21. Dietary berberine supplementation significantly alleviated the compromised average daily gain and average daily feed intake (p < 0.05) caused by LPS. The LPS challenge led to increased lymphocyte and white blood cell (WBC) counts, malondialdehyde (serum and liver) content, and immunoglobulin G and M, tumour necrosis factor‐α (TNF‐α) and interleukin‐1β (IL‐1β) expression (p < 0.05) and significantly reduced serum total superoxide dismutase (T‐SOD) activity (p < 0.05). Dietary berberine significantly mitigated the LPS‐induced decreases in the mRNA expression of nuclear factor‐kappa B (NF‐κB), TNF‐α, IL‐1β, inducible nitrite synthase and cyclooxygenase‐2 (p < 0.05) in the liver. In conclusion, berberine supplementation has a positive effect on LPS challenge, which may be related to the increase in antioxidant enzyme activity and inhibition of both NF‐κB signalling and the expression of inflammatory mediators.     

Effect of gluconic acid on piglet growth performance, intestinal microflora, and intestinal wall morphology

Gluconic acid (GA) derives from the incomplete oxidation of glucose by some Gluconobacter strains. When fed to nonruminant animals, GA is only poorly absorbed in the small intestine and is primarly fermented to butyric acid in the lower gut. This study investigated the effect of GA on in vitro growth response and metabolism of swine cecal microflora and on animal growth performance, intestinal wall morphology, and intestinal microflora. During a 24-h in vitro cecal fermentation, total gas production and maximum rate of gas production were increased by GA (linear, P < 0.001). Ammonia in cecal liquor was reduced by GA after 4, 8, and 24 h of fermentation (quadratic, P < 0.01). After 24 h of fermentation, total short-chain fatty acids, acetic acid, propionic acid, n-butyric acid, acetic to propionic acid ratio, and acetic + butyric to propionic acid ratio were linearly increased by GA (P < 0.001). In the in vivo study, 48 piglets were divided into 4 groups and housed in individual cages for 6 wk. Piglets received a basal diet with a) no addition (control) or with GA addition at b) 3,000 ppm, c) 6,000 ppm, or d) 12,000 ppm. After 6 wk, 4 animals per treatment were killed, and samples of intestinal content and mucosa were collected. Compared with control, GA tended to increase average daily gain (+13 and +14% for GA at 3,000 and 6,000 ppm, respectively; P of the model = 0.11; quadratic, P < 0.05). Daily feed consumption and gain to feed ratio were not influenced by GA. Intestinal counts of clostridia, enterobacteriaceae, and lactic acid bacteria were not affected by GA. Gluconic acid tended to increase total short-chain fatty acids in the jejunum (+174, +87, and +74% for GA at 3,000, 6,000, and 12,000 ppm, respectively; P of the model = 0.07; quadratic, P = 0.07). Morphological evaluation of intestinal mucosa from jejunum, ileum, and cecum did not show any significant differences among treatments. This study showed that feeding GA influences the composition and activity of the intestinal microflora and may improve growth performance of piglets after weaning.     

Effects of dietary Clostridium butyricum supplementation on growth performance,intestinal development,and immune response of weaned piglets challenged with lipopolysaccharide

Background: Weanling pigs, with immature immune system and physiological function, usually experience postweaning diarrhea. This study determined the effects of dietary Clostridium butyricum supplementation on growth performance, diarrhea, and immunity of weaned pigs challenged with lipopolysaccharide(LPS).Methods: In Experiment(Exp.) 1,144 weaned piglets were weaned at 21 d and randomly assigned to six groups,with six replicates per group and four pigs per replicate, receiving a control diet(CON) or diet supplemented with antibiotics(AB) or C. butyricum(CB)(0.1%, 0.2%, 0.4%, or 0.8%), respectively. All diets in Exp. 1 were a highly digestible basal diet, with 3,000 mg/kg zinc oxide supplied in the first 2 wk only. In Exp. 2, 180 piglets were weaned at 21 d and randomly assigned to five groups, with six replicates per group and six pigs per replicate, receiving CON, AB, or CB(0.2%, 0.4%, or 0.6%) diets. The digestibility of diets was lower than those in Exp. 1, and did not include zinc oxide. At 36 d of Exp. 2, 12 piglets were selected from each of the CON and 0.4% CB groups, six piglets were intraperitoneally injected with LPS(50 μg/kg body weight) and the other six piglets with normal saline;animals were killed at 4 h after injection to collect blood, intestine, and digesta samples for biochemical analysis.Results: In Exp. 1, CB and AB diets had no effect on growth performance of piglets. In Exp. 2, 0.4% CB decreased feed-gain ratio(P 0.1), diarrhea score(P 0.05), and increased duodenal, jejunal, and ileal villus height and jejunal villus height/crypt depth(P 0.05). The 0.4% CB decreased the plasma tumor necrosis factor(TNF) α(P 0.05) but increased ileal mucosa IL-10 and TLR2 mRNA expression(P 0.05). Furthermore, 0.4% CB altered the microbial profile, with Bacillus and Ruminococcaceae UGG-003 at genus level and Lactobacillus casei and Parasutterella secunda at species level were higher than CON in colonic content(P 0.05).Conclusions: Dietary C. butyricum supplementation had positive effects on growth of weaned piglets with less digestible diets. There was a tendency to reduce the feed-gain ratio, which could reduce feed costs in pig production. Moreover, C. butyricum decreased post-weaning diarrhea by improving the intestinal morphology,intestinal microflora profile, and immune function.     

Effect of dietary supplementation of oregano essential oils to sows on colostrum and milk composition, growth pattern and immune status of suckling pigs

This study evaluated the effects of supplementing sow diets with oregano essential oils (OEO) during gestation and lactation on sow colostrum and milk composition and on the growth pattern and immune status of suckling pigs. A total of 70 second-parity sows were randomly assigned to 1 of 2 gestation dietary treatments within 24 h after service: control (CON) or CON + 250 mg/kg of OEO (OREG). In lactation, sows were again assigned to either the CON or OREG dietary treatment. Thus, the lactation treatments were CON-CON, CON-OREG, OREG-CON, and OREG-OREG. Colostrum and blood samples were collected from 6 sows per lactation dietary treatment. Thymus lymphocyte (T lymphocyte) subpopulations (γδ, cluster of differentiation 8, and 32 cluster of differentiation 4) were enumerated in blood and mammary secretions along with IGF-1, IgG, and IgA concentrations. Piglet growth rate were determined from 18, 17, 17, and 18 litters from the CON-CON, CON-OREG, OREG-CON, and OREG-OREG lactation dietary treatments, respectively. Growth rates were determined in 630 piglets, and piglets were individually identified and weighed on 1, 5, 9, 12, 16, and 19 d of age. Oregano essential oil supplementation during gestation or lactation had no effect (P > 0.05) on GE, CP, GE:CP, GE:fat, and IGF-1 in sow milk. Reductions of the fat percentage in milk on d 7 (P < 0.05) and d 14 (P = 0.07) were found in sows supplemented with OEO during lactation compared with those in the CON treatment. Milk from sows supplemented with OEO during lactation had the greatest number of T lymphocytes compared with those in the lactation CON treatment on d 14 of lactation (P < 0.01). The number of T lymphocytes in milk was greater for sows in the CON-OREG treatment compared with those other treatments on d 14 of lactation (P < 0.05). Energy intake was greater on d 1 to 5 in piglets from sows fed OEO during gestation than those from sows in the CON treatment (P < 0.05). A trend (P = 0.10) for greater milk intake was observed in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment. Similarly, a tendency for an increase in ADG on d 1 to 5 was found in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment (P = 0.10). Insulin-like growth factor-1 at birth and on d 7 and 14 of lactation did not differ among piglets from sows assigned to the different dietary treatments. Oregano essential oil supplementation of sow diets did not affect (P > 0.05) immunoglobulin concentrations in piglets after suckling. Supplementing sow diets with OEO during gestation or lactation did not affect (P > 0.05) the T lymphocytes, percentage of T-lymphocyte subpopulations, and natural killer cell activity of piglets during lactation. Supplementing sow diets with 250 mg/kg of OEO during gestation and lactation did not affect the growth potential of and immune responses in suckling piglets.     

精氨酸和精氨酸生素对母猪泌乳性能及哺乳仔猪生长性能的影响

为了研究精氨酸和精氨酸生素(AAA)对哺乳母猪泌乳及其仔猪生长性能的影响,试验选用体重和胎次相近的长×大母猪35头,随机分成5组,每组7个重复。对照组饲喂基础日粮,其余4组分别在饲喂基础日粮中添加0.8%精氨酸(Arg),0.03%、0.06%、0.09%AAA。正式试验于妊娠107 d开始,并于母猪生产时耳缘静脉采血分离血浆检测生化指标。试验结果表明,Arg组相对于其余各组显著提高了21日龄仔猪断奶窝重(P<0.05)和日均泌乳量(P<0.05);0.03%AAA组相对于对照组有提高仔猪断奶窝重和断奶均重的趋势(0.05相似文献   

Effect of different concentrations of Bacillus subtilis on growth performance, carcase quality, gut microflora and immune response of broiler chickens

1. An experiment was conducted to study the effects of different Bacillus subtilis concentrations on productivity, carcase quality, immune response and the gut microflora of broiler chickens. 2. There were 5 treatment groups: control, with no added Bacillus subtilis supplementation; and 4 treatment groups receiving feed supplemented with different concentrations of B. subtilis. 3. Weight gain was significantly higher and the feed conversion rate was significantly better in all groups receiving feed supplemented with B. subtilis, regardless of its concentration. The groups given B. subtilis supplementation produced relatively bigger breasts, and smaller carcases and thighs, compared with the control group. 4. The appearance of increased diffuse lymphohistiocytic infiltration and solitary lymphoid follicles in the mucosa, and a stronger response to NDV vaccination, indicate increased immunological responses in chickens fed with the B. subtilis supplemented diet. 5. The higher inclusion rate of B. subtilis did not increase Lactobacillus concentrations in the ileum or in the caecum, but decreased the E. coli population significantly.     

Effect of maternal immunity on the immune response to oral vaccination against rabies in young foxes.

OBJECTIVE: To determine effect of maternal antibodies on immune response to oral vaccination against rabies in young foxes. ANIMALS: 250 cubs from 48 vixens. PROCEDURE: Sera were obtained from cubs of 36 vaccinated (maternally vaccinated [MV+]) and 12 nonvaccinated (MV-) vixens between 23 and 71 days of age and tested for neutralizing antibodies. Seventy-one MV+ cubs and 33 MV-cubs were vaccinated orally with modified-live virus vaccine SAD B19. Geometric mean titer (GMT) was determined in these cubs approximately 21, 39, and 57 days after vaccination. In a subsequent experiment, 10 vaccinated MV+ cubs, 6 vaccinated MV- cubs, and 6 control cubs were challenge inoculated with virulent rabies virus approximately 100 days after vaccination. RESULTS: Serum GMT of nonvaccinated MV cubs (0.23 U/ml) was significantly greater than that of non-vaccinated MV- cubs (0.15 U/ml). The GMT of vaccinated MV+ cubs 21, 39, and 57 days after vaccination were 2.85, 2.11, and 0.79 U/ml, respectively, and were significantly less than those of vaccinated MV- cubs (12.19, 6.76, and 4.02 U/ml, respectively). All challenge-inoculated cubs with GMT < 0.5 U/ml succumbed to rabies. CONCLUSION AND CLINICAL RELEVANCE: Partially impaired immune response in cubs < 8 weeks old from vaccinated vixens causes insufficient protection against rabies. Inhibition of the immune response persists longer than the period during which maternal antibodies are detectable. Thus, oral vaccination campaigns for young foxes in areas where vaccination has been performed need to be reconsidered.     

Effect of corticosterone infusion on plasma corticosterone concentration, antibody production, circulating leukocytes and growth in chicken lines selected for humoral immune responsiveness

The effect of corticosterone on antibody production was studied in chicken lines selected for humoral immune response. 2. Twelve cockerels (33 days old) from lines selected for high or low antibody responses after immunisation with sheep red blood cells (SRBC) were implanted with mini-infusion pumps delivering corticosterone or vehicle continuously for 14 d. 3. Three days after implantation, the chickens were immunised intramuscularly with 0.25 ml packed SRBC. Blood samples were taken before implantation, before immunisation and 3, 5, 7 and 11 d after immunization. 4. Corticosterone infusion induced higher plasma corticosterone concentrations and heterophil/lymphocyte ratios than infusion of vehicle only. Growth was considerably depressed and relative weights of the thymus, bursa of Fabricius and spleen were less in the corticosterone-infused chickens. 5. An effect of corticosterone on antibody production could not be demonstrated, and differences between selection lines were unaffected.     

Effects of fish oil supplementation on the performance and the immunological, adrenal, and somatotropic responses of weaned pigs after an Escherichia coli lipopolysaccharide challenge

Seventy-two crossbred pigs (7.58 +/- 0.30 kg BW) weaned at 28 +/- 3 d of age were used to investigate the effects of fish oil supplementation on pig performance and on immunological, adrenal, and somatotropic responses following an Escherichia coli lipopolysaccharide (LPS) challenge in a 2 x 2 factorial design. The main factors consisted of diet (7% corn oil [CO] or 7% fish oil [FO]) and immunological challenge (LPS or saline). On d 14 and 21, pigs were injected intraperitoneally with either 200 microg/kg BW of LPS or an equivalent amount of sterile saline. Blood samples were collected 3 h after injection for analysis of interleukin-1beta (IL-1beta), prostaglandin E2 (PGE2), cortisol, growth hormone (GH), and insulin-like growth factor (IGF)-I. On d 2 after LPS challenge, peripheral blood lymphocyte proliferation (PBLP) was determined. Lipopolysaccharide challenge decreased ADG (487 vs. 586 g; P < 0.05) and ADFI (as-fed, 776 vs. 920 g; P < 0.05) from d 14 to 21 and ADG (587 vs. 652 g; P < 0.10) from d 21 to 28. Fish oil improved ADG (554 vs. 520 g; P < 0.10) and ADFI (891 vs. 805 g; P < 0.10) from d 14 to 21. On d 14, LPS challenge x diet interactions were observed for IL-1beta (P < 0.10), PGE2 (P < 0.001), and cortisol (P < 0.05) such that these measurements responded to the LPS challenge to a lesser extent (IL-1beta: 93 vs. 114 pg/mL, P < 0.05; PGE2: 536 vs. 1,285 pg/mL, P < 0.001; cortisol: 143 vs. 206 ng/mL, P < 0.05) in pigs receiving the FO diet than in pigs fed the CO diet. In contrast, among LPS-treated pigs, pigs fed the FO diet had higher IGF-I (155 vs. 101 ng/mL; P < 0.10) than those fed the CO diet. On d 21 among LPS-treated pigs, pigs fed FO had lower IL-1beta (70 vs. 84 pg/mL; P < 0.10) and cortisol (153 vs. 205 ng/mL; P < 0.05) than those fed CO. Pigs fed FO had lower PGE2 (331 vs. 444 pg/mL; P < 0.05) and higher IGF-I (202 vs. 171 ng/mL; P < 0.10) compared with those fed CO. Lipopolysaccharide challenge decreased GH (0.27 vs. 0.33 ng/mL; P < 0.05) on d 14, whereas it had no effect on GH on d 21. During both LPS challenge periods, the challenge increased PBLP when these cells were incubated with 8 (1.46 vs. 1.32; P < 0.10) or 16 microg/mL (1.46 vs. 1.30; P < 0.05) of concanavalin A. Fish oil had no effect on PBLP. These results suggest that FO alters the release of proinflammatory cytokines, which might lead to improved pig performance during an immunological challenge.     

延胡索酸和芽孢杆菌对断奶仔猪生产性能及免疫机能的影响

<正>目前,国内外对于酸化剂、益生素在早期断奶仔猪日粮中的应用已有较多的研究,但是,由于试验动物的品种、年龄、试验条件、添加剂量等不同,试验的结果变异很大。以往的试验研究多集中在单一物质对仔猪生产性能的影响,研究酸化剂、益生素在相同条件下的效果比较的试验较少,尤其是对延胡索酸和芽孢杆菌的效果比较、     

保尔福对肉仔鸡生长、微生物菌群及免疫功能的影响

随着我国畜牧业集约化程度的提高和饲料工业的发展,抗生素、化学合成药物和类固醇激素,如促长素、驱虫剂、激素、调味剂、改良剂、色素剂、防腐剂等饲料添加剂也随之普遍使用。这些物质可在畜产品中残留,给人类健康带来严重危害。近些年来,很多国家都兴起了替代抗生素的饲料添加剂研究,都在寻找能够替代抗生素的饲料添加剂。众所周知,巨噬细胞在免疫系统起重要作用,激活的巨噬细胞在机体对抗外来细菌、病毒、真菌及寄生虫的防御机制中作用显著,并已证明巨噬细胞具有抗肿瘤的功能。此外,巨噬细胞可以通过直接作用或间接通过所分泌的各种可溶…     

Effect of direct-fed microbial and antibiotic supplementation on gastrointestinal microflora, mucin histochemical characterization, and immune populations of weanling pigs

Direct-fed microbials (DFM) have the ability to alter gastrointestinal microflora, morphology and immunity. Denaturing gradient gel electrophoresis was used to analyze the effect of Lactobacillus brevis, Bacillus, and antibiotic supplementation on the gastrointestinal microbiota. Treatments were arranged in a 2 × 3 factorial arrangement with two levels of L. brevis supplementation and three diets (control, Bacillus, and antibiotic) fed during the nursery period. Microbial diversity of the gastrointestinal microbiota increased in response to any of the treatments containing L. brevis, Bacillus, or antibiotic compared to unsupplemented pigs. Pigs provided L. brevis and Bacillus in combination exhibited more bands of high G/C content than pigs provided only the antibiotic treatment. Supplementation with L. brevis resulted in a unique band that was identified as unculturable, low G/C content, gram positive bacteria. Furthermore, L. brevis increased pig body weight at the end of the nursery by 1.6 kg compared to pigs not provided L. brevis. L. brevis increased the number of acidic goblet cells present on villi within the duodenum and jejunum, and decreased the number of sulfated goblet cells, whereas Bacillus and antibiotic supplementation decreased the number of sulfated goblet cells on villi within the duodenum. Immunohistochemical evaluation revealed that L. brevis supplementation lowered the number of CD2⁺ cells, antigen presenting cells (MHCII⁺), and CD4⁺ T cells within jejunal villi. These data illustrate the potential for DFM to improve pig growth rate after weaning, as well as elicit alterations in the gut microbial community, mucin-producing goblet cells, and immune cells.     

Effects of dietary supplementation with a chlorella by‐product on the growth performance,immune response,intestinal microflora and intestinal mucosal morphology in broiler chickens

This study aimed to determine the effect of different dietary levels of a Chlorella by‐product (CBP) on the growth performance, immune response, intestinal microflora and intestinal mucosal morphology of broilers. In total, 480 one‐day‐old broiler chickens were randomly allotted to four dietary treatments with four replicated pens consisting of 30 chicks. The basal diet was formulated to be adequate in energy and nutrients. Three additional diets were prepared by supplementing 25, 50 or 75 g/kg of CBP to the basal diet. The diets were fed to the broilers ad libitum for 35 days. Result indicated that increasing inclusion level of CBP improved BW gain (linear, p < 0.05). There was no effect of inclusion level of CBP in diets on total cholesterol, triglyceride, aspartate aminotransferase and alanine aminotransferase levels during the 35 days. Plasma IgG, IgM and IgA concentrations increased (linear, p < 0.05) with inclusion level of CBP in diets. Supplementation of CBP in the diets increased (linear, p < 0.05) the concentrations of Lactobacillus in the caecal content and decreased (linear, p < 0.05) the concentrations of Escherichia coli and Salmonella in the caecal content. Villus height increased (linear and quadratic, p < 0.05) with inclusion level of CBP in diets. Crypt depth increased (quadratic, p < 0.05) with inclusion level of CBP, and a decreased villus height: crypt depth ratio (quadratic, p < 0.05) was observed as inclusion level of CBP in diets increased. The results of the current experiment indicate that dietary supplementation of CBP improves growth performance of birds. Dietary CBP has improving Lactobacillus spp. concentrations in the gastrointestinal tract, plasma immunoglobulin concentrations and intestinal mucosal morphology.     

Effect of dietary probiotic on performance and humoral immune response in layer hens

1. The effects of dietary supplementation of a commercial probiotic (Protexin) on daily feed consumption, egg yield, egg weight, food conversion ratio and humoral immune response in layer hens were investigated. In 7 replicates, a total of 280 40-week-old layers were given diets containing either 0, 250, 500 or 750 parts per million (ppm) for 90 d. 2. When compared with the controls, the food consumption, food conversion ratio and the proportions of damaged eggs were lower in the group consuming 500 ppm probiotic (P<0.05). 3. There was no significant difference between the controls and the groups receiving 250 and 750 ppm probiotic in food consumption, food conversion ratio and proportion of damaged eggs. Similarly, the egg yield, egg weight, specific gravity, and peripheral immune response showed no statistically significant differences between the groups.     

The effects of xylanase supplementation on growth, digestion, circulating hormone and metabolite levels, immunity and gut microflora in cockerels fed on wheat-based diets

1. The xylanase product used in this study was derived from a genetically modified isolate of Aspergillus niger. Two trials were conducted to investigate the effects of xylanase supplementation on growth, digestion, circulating hormone and metabolite levels, immune parameters and composition of the gut microflora in cockerels fed on wheat-based diets. 2. The experimental diets consisted of a wheat-based control diet supplemented with 0 or 0.1% enzyme preparation. The diets were fed between 7 and 21 d of age. 3. Enzyme supplementation improved growth and feed conversion efficiency. The addition of enzyme to wheat-based diet increased the apparent total digestibility of dry matter (DM), crude protein and fat. 4. Enzyme supplementation reduced the relative weight of digestive organs to a certain extent, but there was no significant difference. Enzyme supplementation reduced digesta viscosity in the jejunum. There was no significant difference between the two experimental groups in counts of lactobacillus and coliform bacteria in the caeca. 5. Enzyme supplementation increased the concentration of blood thyroxine (T(4)), insulin-like growth factor I (IGF-I) and insulin, reduced the concentrations of blood uric acid, but had no significant effect on the concentrations of blood glucose and triiodothyronine (T(3)). 6. Enzyme supplementation increased the relative weight of spleen of cockerels, serum antibody titres to Newcastle disease virus (NDV), lymphocyte proliferation in response to phytohaemagglutinin (PHA) and the natural killer (NK) cell activity. 7. It is concluded that supplementation with an enzyme preparation (xylanase), which hydrolyses non-starch polysaccharides can improve growth in cockerels fed on wheat-based diets. This improvement is achieved through enzyme effects on digestion, absorption, metabolism and immunity of cockerels.     

Tasco-Forage: III. Influence of a seaweed extract on performance, monocyte immune cell response, and carcass characteristics in feedlot-finished steers

Tall fescue (Festuca arundinacea Schreb.) infected with the endophyte Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin) causes fescue toxicosis in cattle grazing the forage, but effects of the endophyte were considered to be abated soon after removal of the animals from pastures. Tasco-Forage, a proprietary extract from the brown seaweed Ascophyllum nodosum, is a known source of cytokinins and has increased antioxidant activity in both plants and the animals that graze the forage. Tasco was applied at 0 and 3.4 kg/ha to infected and uninfected tall fescue pastures in Virginia and Mississippi. Forty-eight steers grazed the pastures at each location during each of 2 yr (n = 192) before being transported to Texas for feedlot finishing. On arrival at the feedlot, steers from Tasco-treated pastures had higher (P < 0.01) monocyte phagocytic activity and tended (P < 0.07) to have higher major histocompatibility complex class II expression than steers that grazed the untreated pastures. A depression (P < 0.05) in monocyte immune cell function due to grazing infected fescue was detected throughout the feedlot finishing period but was reversed by Tasco. Rectal temperatures were elevated (P < 0.07) in steers that had grazed the infected tall fescue when they arrived in Texas, but by d 14 no difference was detected. However, by d 28 the temperature effects of infected tall fescue were reversed. Steers that had grazed infected fescue had lower (P < 0.01) rectal temperatures on d 112 of the feedlot period, demonstrating a much longer-lasting effect of the endophyte on thermoregulatory mechanisms than previously thought. Steers that had grazed Tasco-treated pastures had higher (P < 0.01) rectal temperatures on d 56 than steers that had grazed untreated fescue. Steers that had grazed the Tasco-treated pastures had higher marbling scores (P < 0.05) regardless of the endophyte, but no effect of Tasco or endophyte on gain was measured. Our data suggest that Tasco application to tall fescue pastures alleviated some of the negative effects of tall fescue toxicity.     

Effect of an aqueous extract of Azadirachta indica on the immune response in mice.

Because of the very wide spectrum of infectious and non-infectious diseases for which preparations from Azadirachta indica are said to be efficacious, it was suspected that a general immunopotentiating ability could be part of the mechanisms by which it ameliorates so many disease conditions. Using the haemolytic plaque technique, an aqueous extract of Azadirachta indica stem bark was shown to enhance the immune response of BALB/C mice to sheep red blood cells in vivo.     

酵母培养物对保育猪的生长性能、肠道健康和免疫应答的影响

216头断奶仔猪用于测定日粮中添加不同含量的酵母培养物(YC)对断奶仔猪的生长性能、养分消化率、肠道形态结构、肠道菌群和免疫应答的影响,并测定YC是否能够替代抗生素生长抑制剂(AGP)。试验1,28日龄断奶仔猪192头(体重为7.5±0.2kg)随机分配到6个处理组:①对照组(没有添加AGP或YC);②AGP组(氯四环素,80mg/kg);③2.5g/kgYC组(益康XP酵母培养物);④5g/kgYC组;⑤10g/kgYC组;⑥20g/kgYC组。每个处理组8个重复栏,每栏4头断奶仔猪,试验期21d。5g/kgYC组的平均日增重(ADG)高于对照组和其他YC组(p<0.05),而所有YC组AGP组之间没有差异。5g/kgYC组、10g/kgYC组和AGP组的平均日采食量(ADFI)高于对照组(p<0.01);而增重/耗料比(G:F)没有受到影响。因此,试验2选用了添加5g/kgYC的日粮。试验2,24头保育猪(21日龄,体重为5.8±0.1kg)随机分成3个处理组试验21d以阐述YC的作用机理。处理组为:①对照组(没有添加AGP或YC);②AGP组;③5g/kgYC组。每周采集血样测定CD4+、CD8+的百分...