Insulin resistance and compensation in Thoroughbred weanlings adapted to high-glycemic meals

Insulin resistance has been suggested to increase the risk of certain diseases, including osteochondrosis and laminitis. Our objective was to evaluate the effect of adaptation to high-glycemic meals on glucose-insulin regulation in healthy Thoroughbred weanlings. Twelve Thoroughbred foals were raised on pasture and supplemented twice daily with a feed high in either sugar and starch (SS; 49% nonstructural carbohydrates, 21% NDF, 3% crude fat on a DM basis) or fat and fiber (FF; 12% nonstructural carbohydrates, 44% NDF, 10% crude fat on a DM basis). As weanlings (age 199 +/- 5 d; BW 274 +/- 5 kg) the subjects underwent a modified frequently sampled i.v. glucose tolerance test. A series of 39 blood samples was collected from -60 to 360 min, with a glucose bolus of 300 mg/kg BW injected at 0 min and an insulin bolus of 1.5 mIU/kg BW at 20 min. All samples were analyzed for glucose and insulin, and basal samples also were analyzed for plasma cortisol, triglyceride, and IGF-I. The minimal model of glucose and insulin dynamics was used to determine insulin sensitivity (SI), glucose effectiveness, acute insulin response to glucose (AIRg), and disposition index (DI). Insulin sensitivity was 37% less (P = 0.007) in weanlings fed SS than in those fed FF; however, DI did not differ (P = 0.65) between diets because AIRg tended to be negatively correlated with SI (r = -0.55; P = 0.067). This finding indicates that the SI decrease was compensated by AIRg in the weanlings adapted to SS. This compensation was further demonstrated by greater insulin concentrations in SS-adapted weanlings compared with FF-adapted weanlings at 11 of 36 sample points (P < 0.055) and greater (P = 0.040) total area under the insulin curve in SS than in FF weanlings. Plasma cortisol and triglycerides did not differ between dietary groups, but IGF-I was greater (P = 0.001) in SS weanlings. Despite appearing healthy, horses adapted to high-glycemic feeds may exhibit changes in altered insulin sensitivity and compensation that increase the risk of diseases involving insulin resistance. These changes seem to be partially amenable to dietary management.     

苜蓿草颗粒饲料对鹅屠宰性能、器官和血液生化指标的影响

本试验旨在研究苜蓿草颗粒饲料对鹅屠宰性能、器官和血液生化指标的影响。选用21日龄、体重相近(出壳时间和体重基本一致)、健康的扬州鹅300只,将其随机分为5组,分别为对照组、试验Ⅰ组、试验Ⅱ组、试验Ⅲ组和试验Ⅳ组,每组3个重复,每个重复20只,整个饲养试验期7周。前3周添加的苜蓿草粉依次为:0,8%,12%,16%和20%,而后4周添加的苜蓿草粉依次为:0,12%,16%,20%和24%。结果表明,1)42和70日龄,试验Ⅲ组鹅的宰前活重、半净膛重、全净膛重、腿肌重、胸肌重和胫骨重均显著高于对照组(P0.05);2)42和70日龄,试验Ⅱ组鹅胸腺重量和试验Ⅲ组肝脏重量显著高于对照组(P0.05);3)42日龄,试验Ⅰ、Ⅲ和Ⅳ组鹅血清的TG、TC和LDL含量显著低于对照组(P0.05),而HDL则显著高于对照组(P0.05);70日龄,试验Ⅰ、Ⅲ和Ⅳ组鹅血清的TC和HDL含量显著高于对照组(P0.05),而各组TG含量差异不显著。综上所述,苜蓿草粉颗粒饲料能够提高扬州鹅屠宰性能,促进器官发育和改善血液生化指标。从本试验结果来看,21~42日龄和43~70日龄,苜蓿草粉最佳添加水平分别为16%和20%。     

Effects of intravenous xylazine hydrochloride on blood glucose, plasma insulin and rectal temperature in neonatal foals

The effects of intravenous xylazine hydrochloride on blood glucose, plasma insulin and rectal temperature were investigated in six foals at 10 and 28 days of age. These variables were also measured in three foals at 19 days of age when saline alone was injected. Rectal temperature fell significantly after 30 mins in both groups of xylazine treated foals and was still depressed after 120 mins. Hypothermia did not occur in the saline control group. There was no significant change in blood glucose or plasma insulin concentrations during the 120 mins following either xylazine or saline administration and no significant differences between the three groups of foals. When foals were allowed to suckle after being away from their dams for 2 h, there was a significant (P less than 0.01) rise in plasma insulin levels in all the groups. Blood glucose showed a concomitant rise but this was only significant in the saline group. Unlike adults, intravenous xylazine (1.1 mg/kg) does not produce hypoinsulinaemia and hyperglycaemia in foals. This study suggests that the inhibition of insulin release from pancreatic beta-cells by xylazine, which in adults is alpha 2-adrenoceptor mediated, is immature or absent in foals under one month of age.     

Effect of protein source in liquid formula diets on food intake, physiologic values, and growth of equine neonates.

The effects of 2 liquid formula diets differing in protein source were evaluated in orphan foals. The response of 7 foals fed a diet containing casein as the protein source, and 6 foals fed a diet containing a combination of whey and casein, was compared with the response in a reference group of 8 mare-raised foals. Orphaned foals were fed 150 kcal/kg of body weight/d, divided into 6 equal feedings of 25 kcal/kg. Formula intake was comparable among the experimental groups, and foals fed the liquid formula diet grew as well as mare-raised foals. There was no difference among groups in mean daily body weight gain, wither height, heart girth, body temperature, pulse, respiration rate, capillary refill time, or skin tenting. Insulin and blood glucose concentrations increased in both groups of foals fed formula diets, returning to prefeeding values within 4 hours. Differences among groups were found for serum alkaline phosphatase, alanine transaminase, cholesterol, creatinine, and glucose values; all other serum chemical values were comparable among groups. Plasma amino acid determinations revealed that arginine and ornithine were significantly lower in foals in both experimental groups than in reference foals, suggesting that arginine may have been the limiting amino acid in these diets. Diarrhea developed in foals in all treatment groups, but in most cases was self-limiting. These results suggest that the protein source of liquid formula diets may be less important in foals than in infants.     

泌乳驴的日粮蛋白水平对驴驹生长发育的影响

试验旨在研究泌乳驴的日粮蛋白水平对驴驹生长发育的影响。选取健康、体况良好的5岁龄、胎次(1.9±0.4)胎、体重(240±30) kg、泌乳日期(29±5) d的带驹德州三粉驴24头,分为3个处理组(H、M、L组),饲喂蛋白水平分别为13.18%、12.22%和11.34%的日粮。每个处理组4个重复,每个重复2头驴。正式试验期8周,分为试验前期(1~4周)和试验后期(5~8周)。同时,将24头驴驹跟随母驴相应分为3个处理组,驴驹的公、母比例一致,日龄(29±5) d与体重(48±8) kg相近。所有驴驹除摄取母乳外,补饲数量相同的精补料与粗饲料。试验表明,试验前期泌乳驴的日粮蛋白水平对驴驹日增重无显著的影响(P>0.10);试验后期,随着泌乳驴日粮蛋白水平的增加,驴驹日增重显著增加(P<0.05),饲料转化效率呈一定增加趋势,但对体尺无显著影响(P>0.10)。饲喂泌乳驴高蛋白水平日粮对驴驹血浆中天冬氨酸(Asp)、苏氨酸(Thr)、丝氨酸(Ser)和组氨酸(His)的含量有明显的促进作用。提高泌乳驴的日粮CP水平,对驴驹日增重具有一定促进作用,以12.22%和13.18%的效果较好。     

Effects of ochratoxin A on some production traits, lipid peroxide and glutathione redox status of weaned piglets

The effect of feeding ochratoxin A (OTA) contaminated diet (379.6 and 338.1 microg/kg in starter and grower diets) on production traits, lipid peroxidation and some parameters of the glutathione redox system were investigated in weaned piglets over a seven-week period. Feed intake and feed conversion ratio (FCR) did not differ significantly, but in the first phase (0-28 days) the daily weight gain was significantly lower in the piglets fed the OTA-contaminated diet. Lipid peroxidation, as measured by the amount of malondialdehyde, glutathione content and glutathione peroxidase activity, did not change significantly in the blood plasma and red blood cell haemolysate in the OTA-loaded group, while malondialdehyde content increased significantly in the liver and markedly but not significantly in the kidney of piglets fed OTA-contaminated feed. Glutathione content did not differ significantly in the studied organs of the two groups while glutathione peroxidase activity of the OTA-loaded animals was significantly lower both in the liver and in the kidney. The results suggest that the use of feed-stuffs contaminated with low levels of OTA for seven weeks did not cause marked differences in the production traits or in lipid peroxidation and amount or activity of the glutathione redox system in the blood plasma, red blood cells and kidney, while significant changes occurred in the liver homogenate.     

Response of animals to dietary gramine. II. Effects of feeding high-gramine yellow lupin seeds on reproductive performance of rats and on selected hematological and biochemical parameters in offspring.

Two groups of 26 male and 26 female rats at the initial age 30 +/- 2 days were fed during 31 weeks on diets containing 20 percent of yellow lupin seeds having low (LG) or high (HG) gramine content. The animals were mated twice within nutritional groups, 1 male: 1 female, and their main reproductive parameters were recorded. In both reproductive cycles body weight of females at mating, after parturition and after 21-days lactation was lower in HG than in LG group. Fertility rate and body weight of neonates were not affected by the diet while number of neonates per litter tended to be lower by 0.7 and 0.8 pups in HG than in LG group. Body weight of weaners was also substantially smaller in dams fed on HG than LG diet. Relative weight of spleen but not of liver, kidney and heart was significantly greater in HG females. Four weeks old males and females issued from the first litters born to LG and HG animals (ten males and ten females per treatment) were fed individually on respective diets during 3 weeks. Feed intake and growth rate did not differ between the treatments. In males relative weight of liver and testicles was greater, while hematocrit and red blood count were lower in HG than in LG group. In females organ weights did not differ. Activity of liver enzymes determined in males was not affected by the diet. It may be concluded that high-gramine lupin affects negatively lactational performance, probably via lower feed intake, but it does not induce apparent teratogenic effects in the progeny.     

Effects of dietary sewage solids on feedlot performance, carcass characteristics, serum constituents and tissue elements of growing lambs

Twenty fine-wool wether lambs were allotted randomly at weaning to be fed a conventional diet (CD) formulated for growing lambs, or the same basal mixture plus dried gamma-irradiated solids from primary sewage sludge (SS) incorporated as 7% of the dry matter. Feedlot performance and chemical elements in whole blood were monitored during 90 d, after which lambs were slaughtered and carcass data were collected. Concentrations of Ag, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb and Zn were measured in livers, kidneys, bones, spleens and muscles. Sewage solids in the diet did not affect performance appreciably, although dressing percentages from lambs fed SS were 4% lower than CD-fed animals (P less than .05). Rib eye areas, fat thicknesses, quality and yield grades were similar (P greater than .05). Element concentrations in whole blood at weaning, after 56 d of the feeding trial and at slaughter did not differ (P greater than .05) between dietary groups. Serum chemistry determinations showed no biologically meaningful patterns related to diets. Lambs fed SS had higher (P less than .05) concentrations of Cu in livers (51.1 vs 34.3 +/- 3.8 micrograms/g, mean +/- SE) and Pb in kidneys (4.0 vs 2.2 +/- .3 micrograms/g) and lower (P less than .05) Mg in kidneys (.69 vs .72 +/- .01 mg/g). None of the elements in spleen and muscle tissue differed (P greater than .05) between diet groups. Lambs fed SS had elevated (P less than .05) bone Co, Cu, Fe, K and Na compared with those of CD.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of dietary electrolyte balance on production, immune response and mineral concentrations of the femur in broilers

The aim of this study was to assess the age-related effects of dietary electrolyte balance (DEB) on the performance, immune response (from day 0 to 42) and macromineral content of femur ash of broilers. The DEB values of the purchased commercial broiler diets were modified with the addition of NH4Cl or NaHCO3 to formulate the diets (DEB 325, 250, 175, 100, 25 and -50 mmol/kg) for this investigation. A total of 396 chickens were divided into 6 treatment groups and fed with the experimental diets for 6 weeks. During the first two weeks of life, DEB did not influence feed intake and body weight gain; however, by the 21st day of age DEB 175 and between 22 and 42 days of age DEB 250 mmol/kg gave significantly better results than the control. DEB did not affect the macromineral concentrations of bone ash. The immune response of broilers on low DEB (< 175 mmol/kg) was faster and more intensive than that of chickens on diets with medium or high DEB (> 175 mmol/kg). It can be concluded that the optimal DEB value required for the best body weight gain is significantly influenced by the age of broilers. Our results call attention to the discrepancy between the decreasing DEB level of commercial broiler diets and the age-related increase of 'electrolyte requirements' of broilers. It is also interesting that DEB may influence not only the performance but also the immune response of broilers.     

The effect of different dietary levels of a n-paraffin-grown yeast on the growth and food intake of broiler chicks

Sixteen groups, each of about 30 male or female Ross 1 chicks, were given pelleted diets containing 0, 5, 10 or 20% yeast in place of herring meal. The diets were given from 1 d of age for 4 weeks; from 4 to 8 weeks the birds were given a common broiler finisher diet. Replacing up to 10% herring meal by yeast did not significantly affect live‐weight at 4 weeks of age but food conversion efficiency was poorer with the diet containing 10% yeast. Birds given the diet containing 5% yeast to 4 weeks of age were significantly heavier at 8 weeks. The diet with 20% yeast significantly depressed growth at 4 and 8 weeks of age.

The use of yeast in broiler finisher diets was investigated in a second experiment. Birds similar to those used in the first experiment were given diets containing yeast at levels of 0, 5, 10 or 20% from 4 to 8 weeks of age. Live‐weight at 8 weeks was not significantly affected by level of yeast in the diet; food conversion efficiency was significantly better with the 20% yeast diet. Blood plasma uric acid levels were not affected by the level of yeast in the diet.     

Utilization of potato peels and sugar beet pulp with and without enzyme supplementation in broiler chicken diets: effects on performance,serum biochemical indices and carcass traits

This study was conducted to investigate the effects of including potato peels (PP) and sugar beet pulp (SBP), as unconventional feeds, with and without enzyme in broiler diets from 1 to 42 days of age by observing the growth performance, blood parameters and carcass characteristics. A total of 150, 1‐day old, chicks were randomly assigned into five groups, each with 30 chicks. Birds in group 1 were fed on the control diet. Chicks in groups 2 and 3 were offered diets containing PP and SBP at the rate of 15% and 7.5%, respectively, while those in groups 4 and 5 were fed the same diets but with adding an enzyme mixture. Using the unconventional feeds in the diets was found to decrease the body weight (BW). However, the feed intake, weight gain and feed conversion did not differ from the control in PP at the grower period, but decreased in SBP throughout the experiment. Addition of enzyme greatly improved the BW in PP and SBP to a degree that it surpasses the control and also increased the feed intake and conversion. The total cholesterol and low‐density lipoprotein cholesterol serum levels were decreased in all tested groups. Carcass yield was not affected by treatments, but the carcass fat content was reduced using the unconventional feeds with or without enzyme. In conclusion, PP can be used at a rate of 15% in the grower diets of broilers. Furthermore, 15% PP or 7.5% SBP can be included in starter and grower diets, but with the addition of enzymes. This can help in solving the problem of current shortage and rising costs of conventional feeds.     

Effects of peach palm oil on performance, serum lipoproteins and haemostasis in broilers

1. An experiment was conducted to study the comparative effects of peach palm oil (PPO, Bactris gasipaes H.B.K), crude palm oil (CPO, Elaeis guinenesis), maize oil (MO) and beef tallow (BT) on serum total and lipoprotein cholesterol levels and haemostatic factors in broiler chickens. 2. Four experimental diets were formulated to be isocaloric (14·2 MJ AME(N)/kg) and isonitrogenous (230 g CP/kg). PPO was extracted from the whole dry fruit with hexane. Each fat was added to the diet in an amount equivalent to 25% of total dietary calories. Six replicate groups of eight male broiler chicks were assigned randomly to each dietary treatment. Diets were fed on ad libitum basis. The experiment lasted 42 d. 3. At 42 d, birds were fasted overnight and three chickens/dietary treatment were utilised to draw blood for lipoprotein separation. Various haemostatic factors were determined in thrombocyte-poor plasma. Thrombocyte aggregation was assayed in whole blood. 4. No significant differences were detected in body-weight gain or feed efficiency between the chickens fed on the PPO diet and those receiving the CPO, MO or BT diets. Total serum cholesterol (TC), very low density lipoprotein cholesterol and low density lipoprotein cholesterol (LDL(C)) were not significantly affected after consuming the PPO, CPO and MO diets. Serum high density lipoprotein cholesterol (HDL(C)) was reduced only by the MO diet. Birds fed on the PPO diet had a significantly lower [corrected] LDLC/HDLC ratio compared with other dietary treatments 5. Thrombocyte count and thrombin time were not significantly affected by the experimental diets. Dietary oils significantly affected prothrombin time, fibrinogen concentration and thrombocyte aggregation. PPO and MO diets elicited the lowest fibrinogen levels compared to the CPO and BT diets. Thrombocyte aggregation in broilers fed on the PPO diet was similar to that of the CPO, MO and BT diets. 6. The results suggest that PPO might efficiently provide up to 25% of dietary energy in broiler diets. Additionally, PPO elicited a more favourable LDL(C)/HDL(C) ratio and haemostatic pattern in broiler chickens. These findings may be of general interest to the food industry.     

Nitrogenous constituents in plasma of foals weaned at three, four or six months of age

A study was conducted to measure the nitrogenous constituents in the blood of foals weaned at 3, 4 or 6 months of age (four foals per weaning age).Jugular blood was sampled from one week prior to weaning until one month post-weaning, and was analyzed for total protein, albumin, creatinine, urea Nitrogen and free amino acid content. Results indicated that the concentrations of most of the constituents in the blood of foals were not altered by the age of weaning, however, free amino acids decreased as age at weaning increased and creatinine was significantly higher in foals weaned at 6 months of age. Plasma creatinine, lysine and methionine levels generally decreased between pre-weaning and one month post-weaning. These data establish baseline values for blood nitrogenous constituents in foals at weaning.     

The influence of dietary palm olein, fish oil and lard on the egg yolk and plasma lipid composition, and performances of laying hens

The influence of dietary palm olein, in comparison to fish oil and lard, on lipid levels in egg yolk and blood plasma, the fatty acid composition of egg yolk, and various production parameters were studied. Brown Lohman laying hens (n=45) were randomly assigned into three groups of 15 birds, and treated with experimental diets with either 3% palm olein (PO), fish oil (FO) or lard (L) for 6 weeks. At the end of the experiment, feed consumption was significantly lower for hens fed the PO diet, except week 6 of the experiment. The concentration of plasma triglycerides was increased by all experimental diets, whereas there were no significant increases of plasma total lipid and total cholesterol concentrations only in the PO group. For yolk lipids a decrease in triglycerides in the FO and L groups was observed, while total cholesterol and total lipid were significantly decreased in the PO group. Feeding with the PO diet resulted in the lowest concentrations of palmitic, stearic and linoleic acid, as well as in the highest concentration of monounsaturated oleic acid in the yolk total lipid. It was concluded that the composition of yolk lipids did not closely match the concentrations of lipids observed in experimental diets or plasma. Based on the current work it seems that the PO diet modulates egg yolk lipid content best.     

4种植物提取物对肉鸡氨气散发、生长性能及血液生化指标的影响

研究旨在观察比较樟科（CFPE）、丝兰（YE）、一串红（SS）和桂花（OFL）植物提取物对肉鸡氨散发量、生产性能、免疫机能以及血液生化指标的影响。将500只0日龄AA肉鸡随机分为5组：即肉桂、丝兰、一串红和桂花提取物200mg/kg添加试验组,及基础日粮对照组。每个试验组4个重复,每个重复25只。结果表明,与对照组相比,各试验组均显著降低氨气的散发（P〈0.05）,提高日增重,降低料肉比（P〈0.05）,显著改善肉鸡血液生化指标（P〈0.05）：增高血清总蛋白的含量,降低血清尿素氮、血清尿酸含量和黄嘌呤氧化酶的活性;同时,桂花组显著提高血液中CD4^＋的含量和CD4^＋/CD8^＋,降低CD8^＋的含量（P〈0.05）。结果提示,日粮中添加肉桂、丝兰、一串红、桂花提取物均能显著改善肉鸡生长性能,增强机体免疫机能,且在降低鸡舍中的氨气浓度,改善饲养环境方面,一串红、桂花植物提取物完全可以达到甚至超过樟科、丝兰植物提取物的作用效果。     

Long-term effects of early antibiotic intervention on blood parameters,apparent nutrient digestibility,and fecal microbial fermentation profile in pigs with different dietary protein levels

Backgroud: This study aimed to determine the effects of early antibiotic intervention(EAI) on subsequent blood parameters, apparent nutrient digestibility, and fecal fermentation profile in pigs with different dietary crude protein(CP) levels. Eighteen litters of piglets(total 212) were randomly allocated to 2 groups and were fed a creep feed diet with or without in-feed antibiotics(olaquindox, oxytetracycline calcium and kitasamycin) from postnatal d 7 to d 42. On d 42, the piglets within the control or antibiotic group were mixed, respectively, and then further randomly assigned to a normal-(20%, 18%, and 14% CP from d 42 to d 77, d 77 to d 120, and d 120 to d 185,respectively) or a low-CP diet(16%, 14%, and 10% CP from d 42 to d 77, d 77 to d 120, and d 120 to d 185,respectively), generating 4 groups. On d 77(short-term) and d 185(long-term), serum and fecal samples were obtained for blood parameters, microbial composition and microbial metabolism analysis.Results: EAI increased(P 0.05) albumin and glucose concentrations in low-CP diet on d 77, and increased(P 0.05) urea concentration in normal-CP diet. On d 185, EAI increased(P 0.05) globulin concentration in normal-CP diets, but decreased glucose concentration. For nutrient digestibility, EAI increased(P 0.05)digestibility of CP on d 77. For fecal microbiota, the EAI as well as low-CP diet decreased(P 0.05) E. coli count on d 77. For fecal metabolites, on d 77, EAI decreased(P 0.05) total amines concentration but increased skatole concentration in low-CP diet. On d 185, the EAI increased(P 0.05) putrescine and total amines concentrations in low-CP diets but reduced(P 0.05) in the normal-CP diets. The low-CP diet decreased the concentrations of these compounds.Conclusions: Collectively, these results indicate that EAI has short-term effects on the blood parameters and fecal microbial fermentation profile. The effects of EAI varied between CP levels, which was characterized by the significant alteration of glucose and putrescine concentration.     

Insulin sensitivity of heifers on different diets

The hyperinsulinemic euglycemic clamp technique was used to investigate the effect on insulin sensitivity of 2 different diets used in practical cattle feeding in calves. Ten 4 to 5-month-old heifer calves were allocated to 2 feeding groups, LO or HI, to obtain growth rates of 400 g/day or 900 g/day. The heifers were fed and housed individually for 5 weeks. Growth rates close to calculated rates were obtained with the diets used. Weekly blood samples were collected from the jugular vein for analysis of glucose, insulin, cortisol, total serum protein, urea, cholesterol and non-esterified fatty acids. During week 5, insulin sensitivity was estimated using the hyperinsulinemic euglycemic clamp technique. Insulin sensitivity did not differ between the groups, but the plasma glucose levels were higher during weeks 3 and 4 for the HI group compared to the LO group. It may be concluded that the amount of concentrate in the diet was too low to induce changes in either the basal plasma insulin levels or the insulin sensitivity in the HI group.     

Effects of oral supplementation with β-carotene on concentrations of β-carotene, vitamin A and α-tocopherol in plasma, colostrum and milk of mares and plasma of their foals and on fertility in mares

In this study, effects of oral β-carotene supplementation to mares (β-carotene group: 1000 mg/day, n = 15; control group: n = 15) from 2 weeks before foaling until 6 weeks thereafter on concentrations of β-carotene, vitamin A and α-tocopherol in plasma, colostrum and milk and plasma of their foals were determined. In addition, effects on fertility were studied. Beta-carotene concentrations increased in plasma and colostrum of β-carotene-supplemented mares compared to control mares (p < 0.05). In mares of both groups, β-carotene concentrations were higher in colostrum than in milk (p < 0.05). In foals, β-carotene concentrations increased with colostrum uptake and were higher in foals born to supplemented mares (p < 0.05; control group: 0.0003 ± 0.0002 μg/ml on day 0, 0.008 ± 0.0023 μg/ml on day 1; β-carotene group: 0.0005 ± 0.0003 μg/ml on day 0, 0.048 ± 0.018 μg/ml on day 1). Concentrations of vitamin A and α-tocopherol were higher in colostrum than in milk (p < 0.05) but did not differ between groups. Concentration of α-tocopherol in plasma of mares decreased over time and in foals, increased markedly within 4 days after birth. All but one mare (control group) showed oestrus within 2 weeks post-partum. Occurrence of oestrus did not differ between groups. More mares of the control group (7/7 vs. 5/12 in the β-carotene group) became pregnant after being bred in first post-partum oestrus (p < 0.05). In conclusion, β-carotene supplementation to mares increased β-carotene concentrations in plasma, colostrum and milk of mares and plasma of their foals but had no positive effects on fertility.     

不同类型饲粮和添加剂对肉仔鸡生长性能、肠道结构和功能的影响

本试验旨在研究不同类型饲粮和添加剂对肉仔鸡生长性能、肠道结构和功能的影响。试验采用4×3两因子完全随机设计,4种饲粮分别为抗生素饲粮、无抗生素饲粮、低蛋白质饲粮和大麦饲粮,3种添加剂分别为酵母培养物(XPC)、谷氨酰胺(Gln)和大豆异黄酮(ISF)。试验选用1日龄爱拔益加肉仔鸡792只,随机分为12组,每组6个重复,每个重复11只鸡。试验期42 d。结果表明:1)不同类型饲粮分别添加XPC、Gln和ISF对42日龄肉仔鸡平均日增重(ADG)、平均日采食量(ADFI)、料重比(F/G)及体重(BW)的影响无显著差异(P0.05);但对饲粮类型而言,与其他3种饲粮相比,低蛋白质饲粮使肉仔鸡的BW、ADG和ADFI显著降低(P0.05),F/G显著提高(P0.05);抗生素饲粮显著降低肉仔鸡的F/G(P0.05)。饲粮类型与添加剂对肉仔鸡生长性能无显著的互作效应(P0.05)。2)与添加Gln相比,抗生素饲粮中添加ISF显著改善19日龄肉仔鸡回肠形态(P0.05);低蛋白质饲粮中添加XPC与添加其他2种添加剂相比对肉仔鸡回肠形态有显著改善作用(P0.05);与添加XPC相比,大麦饲粮中添加ISF显著改善19日龄肉仔鸡回肠形态(P0.05)。除35日龄肉仔鸡回肠隐窝深度外,饲粮类型与添加剂对回肠形态存在显著的互作效应(P0.05)。3)大麦饲粮中添加XPC比添加Gln和ISF显著提高35日龄肉仔鸡回肠干扰素-γ水平(P0.05);与添加ISF相比,抗生素饲粮中添加XPC可显著提高19日龄肉仔鸡回肠白细胞介素-10(IL-10)和免疫球蛋白A(Ig A)水平(P0.05),添加Gln可显著提高35日龄肉仔鸡回肠Ig A水平(P0.05);低蛋白质饲粮中添加XPC比添加其他2种添加剂显著提高19日龄肉仔鸡回肠Ig A水平(P0.05);无抗生素饲粮中添加ISF比添加XPC显著提高35日龄肉仔鸡回肠IL-10和Ig A水平(P0.05);而大麦饲粮中添加ISF比添加XPC显著降低35日龄肉仔鸡回肠IL-10水平(P0.05)。对于回肠IL-10和Ig A水平,饲粮类型与添加剂之间存在显著互作效应(P0.05)。4)抗生素饲粮中添加XPC比添加其他2种添加剂显著降低19日龄肉仔鸡粪便中氮和磷残留率(P0.05);无抗生素饲粮中添加XPC比添加其他2种添加剂显著提高19日龄肉仔鸡粪便中氮和磷残留率以及35日龄肉仔鸡粪便中磷残留率(P0.05);低蛋白质饲粮中添加XPC比添加Gln显著降低19日龄肉仔鸡粪便中氮残留率(P0.05);大麦饲粮中添加Gln比添加其他2种添加剂显著降低19日龄肉仔鸡粪便中氮和磷残留率(P0.05)。对氮、磷残留率而言,饲粮类型与添加剂之间存在显著互作效应(P0.05)。由此可见,4种类型饲粮中添加3种添加剂对1~42日龄肉仔鸡生长性能无显著影响;能氮比固定的低蛋白质饲粮降低了肉仔鸡的生长性能;低蛋白质饲粮中添加XPC可改善回肠形态结构;在不同类型饲粮中添加不同的添加剂具有改善肉仔鸡回肠免疫状态及降低粪便中氮磷残留率的趋势。     

酵母硒对肉仔鸡的生物安全性评价

本试验旨在研究饲粮添加不同水平酵母硒对爱拔益加(AA)肉仔鸡生长性能、血液血红蛋白含量和红细胞压积、血浆生化指标、器官指数和组织结构变化的影响,进而评价酵母硒对肉仔鸡的生物安全性。试验采用单因子完全随机设计,选用288只1日龄AA肉仔鸡,随机分为4个组,每个组6个重复,每个重复12只鸡(公母各占1/2)。各组分别在玉米-豆粕型基础饲粮中添加0、0.4、2.4和4.9 mg/kg(以硒计)的酵母硒试验。试验期为42 d。结果表明:1)与对照组相比,饲粮添加0.4和2.4 mg/kg酵母硒显著提高了22~42日龄肉仔鸡平均日采食量(P0.05);饲粮添加0.4、2.4和4.9 mg/kg酵母硒显著提高了1~42日龄肉仔鸡平均日增重(P0.05),而各酵母硒添加组之间差异不显著(P0.05)。2)饲粮添加不同水平酵母硒除对21日龄肉仔鸡血浆尿素氮含量和谷胱甘肽过氧化物酶(GSH-Px)活性以及42日龄肉仔鸡血浆GSH-Px活性有显著影响(P0.05)外,对其他血浆生化指标均无显著影响(P0.05)。与对照组相比,各酵母硒添加组21和42日龄肉仔鸡血浆GSH-Px活性随着酵母硒添加水平的增加均显著提高(P0.05),且饲粮添加2.4 mg/kg酵母硒显著降低了21日龄肉仔鸡血浆尿素氮含量(P0.05)。3)饲粮添加不同水平酵母硒对21和42日龄肉仔鸡血液血红蛋白含量和红细胞压积及42日龄肉仔鸡器官指数均无显著影响(P0.05),且并未引起主要器官的组织结构变化。综上所述,肉仔鸡饲粮中酵母硒的添加水平为0.4 mg/kg(饲粮中总硒含量为0.41 mg/kg)时,具有10倍的安全系数,即饲粮中以酵母硒形式添加硒对肉仔鸡是安全的。