生长期中华鳖体内营养物质沉积率与饵料营养水平的关系研究

以150g左右、健壮的170只中华鳖为试验动物,随机分为17个组(其中1个组为“对照组)。以饵料能量、蛋白质为试验因素,采用2因子5水平回归正交旋转组合设计,得到9个试验饵料配方及其营养组合,进行60d饲养试验。试验表明,第9组鳖和第10～16组鳖平均体增重最高为2.22g/d,能量(GE)、蛋白质(CP)、脂肪(EE)和氨基酸(AA)沉积率分别达到36.27%、56.48%、55.06%和43.66%。试验条件下鳖体内营养物质沉积率与饵料配方营养水平及其组合有密切相关关系,9号饵料配方、营养水平及其组合比较适宜于生长期鳖的需要。       

应激安散对早期断奶仔兔生产性能和腹泻率的影响

为了探讨纯中药制剂应激安散对早期断奶仔兔生产性能和腹泻率的影响,选用30±2日龄体重相近的断奶仔兔120只,随机分为4个处理组进行试验。本试验结果显示,YJA-Z组和YJA-G组可显著提高断奶仔兔的平均日增重、平均日采食量,降低料重比,表明应激安散能够有效抵抗断奶应激对仔兔造成的伤害,显著促进其生长。     

生长期SD大鼠对日粮常规营养物质和氨基酸消化率的研究

目的了解SD大鼠对营养物质消化特点,研究不同结构日粮营养物质的可消化性,为筛选适合SD生长大鼠的日粮营养物质水平和日粮配方提供科学参数. 方法采用饲养试验结束时的90 d龄体重相近的90只SD大鼠,分为9个组,每组10 只,雌雄各半,分笼、每笼5只,采用全收粪法对9个配方日粮进行5 d消化试验,测定9个日粮的能量和6种常规营养物质以及17种氨基酸(AA)的表观消化率.结果以第3组日粮的可消化性为最好,它的总能(GE)、粗蛋白(CP)、粗纤维(CF)、粗脂肪(EE)、无氮浸出物(NFE)、钙(Ca)、磷(P)和17种氨基酸的表观消化率(%)依次分别为85.7、88.0、2 9.5、89.2、90.0、47.6、35.7和85.0(17个氨基酸AA平均值);这些营养物质在9个组的总平均表现消化率(%)依次分别为82.1、79.1、24.7、84.9、88.4、37.1、33.1和 81.5,结果表明,生长期SD大鼠对不同结构的日粮,不同水平的营养物质的可消化性不同 ,不同营养物质的消化率差别较大,以第3组日粮配方及其营养水平较适宜于生长期SD大鼠 ,它的DE、CP、EE、CF、NFE、Ca和P水平依次为14MJ.kg-1、18%、4.5%、4.0%、5 5.0%、1.00%和0.66%,它的苏氨酸,胱氨酸、缬氨酸、蛋氨酸、异亮氨酸、亮氨酸、酪氨酸、苯丙氨酸、赖氨酸、组氨酸和精氨酸水(%)依次为0.74、0.38、1.00、0.40、0. 93、1.65、0.62、0.94、1.00、0.58和1.22,它的可消化氨基酸水平(%)依次为0.60 、0.29、0.84、0.31、0.76、1.45、0.52、0.82、0.87、0.52和1.12.结论日粮能量具有较高的可消化性,对于其他营养物质的消化吸收利用有正效应影响.     

不同浓度下的中药复方对四川白兔生长的影响

本次研究旨在探讨中药复方对四川白兔生长性能、免疫功能及其抗氧化情况的作用。采用单因子实验设计,选择30日龄断奶四川白兔仔兔100只,随机分为5组(每组20只,雌雄各半),试验3组为高浓度组(基础日粮+3%中药添加剂),试验2组为中等浓度组(基础日粮+2%中药添加剂),试验1组为低浓度组(基础日粮+1%中药添加剂),试验4组为阳性组(基础日粮+1%杆菌肽锌+1%硫酸黏杆菌素),对照组饲喂基础日粮。试验期为56 d,其中预试期为7 d,正试期为49 d。正试期内测定试兔的生长性能,试验结束时测定试兔的抗氧化和免疫指标。结果显示:高浓度组显著提高了兔的Ig M (p<0.05),中等浓度组极显著提高了兔的Ig A (p<0.01),且死亡率均为0;低浓度组和高浓度组显著提高了兔丙二醛(MDA)或超氧化物歧化酶(SOD)的活性;低浓度组显著提高了兔的脾指数(p<0.05);高浓度组显著提高或降低了兔十二指肠的绒毛高度或隐窝深度(p<0.05);中等浓度组显著提高了回肠的绒毛高度(p<0.0.5)。饲粮添加一定的中药复方不仅能改善兔子的生长性能,增强四川白兔的免疫能力及抗氧化性,也可以降低四川白兔死亡发生概率。     

中药渣发酵物对母猪繁殖性能和血浆指标的影响

为了探讨中药渣发酵物在母猪饲粮中的添加效果,试验选用2~6胎次长白×大白二元妊娠母猪32头,随机分为对照组和试验组,单栏饲养。于妊娠90 d至产后28 d,对照组饲喂基础饲粮,试验组在基础饲粮中添加0.5%中药渣发酵物。于分娩当天记录产活仔数、死胎数和木乃伊数,称取仔猪出生窝重;于产后21 d称取仔猪断奶窝重,计算断奶窝增重。分别于母猪妊娠110 d及产后21 d测量母猪的背膘厚,计算背膘损失;于分娩当天和产后21 d耳缘静脉采集母猪血液,肝素抗凝,离心分离血浆,用于血浆生化参数和抗氧化性能指标测定。结果表明:与对照组相比,试验组仔猪的断奶窝增重有升高趋势(P=0.068),断奶后1~7 d发情率呈升高趋势(P0.05),分娩当天血浆ALT活性和MDA含量显著降低(P0.05)、UN浓度显著升高(P0.05),产后21 d血浆AST活性显著降低(P0.05)、UN浓度显著升高(P0.05)、SOD活力有升高趋势(P=0.063)。上述结果表明,中药渣发酵物可在一定程度上提高母猪的繁殖性能、增强抗氧化能力,增加仔猪断奶窝增重。     

小肽营养素对断奶仔猪生产性能及血液生化指标的影响

本试验将40头21 d断奶的三元杂交猪随机分为4组,用4组不同日粮组成及营养水平的饲料(I:基础日粮+2%喷雾干燥血浆蛋白粉(SDPP);Ⅱ、Ⅲ和Ⅳ组分别在基础日粮中添加1%,2%和3%小肽营养素)饲养21 d后称重、测定血液生化指标并进行统计分析.结果表明:添加小肽营养素对断奶仔猪的生产性能无显著影响;各处理组的血清总蛋白、血糖和血清尿素差异不显著,2%小肽组的球蛋白、免疫球蛋白含量显著高于其它组;小肽产品可以部分等蛋白取代断奶仔猪日粮中的血浆蛋白粉.通过了解小肽营养素替代喷雾干燥血浆蛋白粉对21 d断奶仔猪的生产性能和血液生化指标的影响,为肽类产品在断奶仔猪日粮中的应用提供了依据.     

大豆寡糖对断奶环江香猪生长性能和营养物质代谢的影响

为了探讨大豆寡糖(SBOS)作为抗生素替代物对断奶仔猪生长性能的影响及其作用机制,饲养试验选用21日龄断奶的环江香猪12头,随机分为2组,每组6头,分别饲喂添加0.5%SBOS日粮和抗生素对照日粮,试验期为14 d。记录每天的采食量,分别于试验开始和结束时称取空腹体重并采集血液,肝素抗凝离心分离血浆,测定生化参数和游离氨基酸水平。消化试验选用10头环江香猪,随机分为2组,处理同饲养试验。预试期4 d,正试期3 d,收集粪样,指示剂法测定干物质、粗蛋白和粗脂肪的消化率。结果表明,与抗生素对照组相比,SBOS组仔猪平均日采食量、日增重和料重比均无显著变化;血浆尿素氮和血氨含量显著下降,总蛋白含量显著升高(P<0.05);血浆甘氨酸、组氨酸、赖氨酸、精氨酸和蛋氨酸的含量均显著升高(P<0.05);粗蛋白和粗脂肪消化率有提高趋势。提示SBOS可替代抗生素用于断奶仔猪日粮。     

刺五加提取物对断奶仔猪血常规和抗氧化功能的影响

为研究日粮添加刺五加提取物对断奶仔猪血常规和抗氧化功能的影响,选择21日龄断奶仔猪60头,随机分为3个处理,每个处理20个重复,单栏饲养,分别饲喂基础日粮+0.1%刺五加提取物、基础日粮+0.02%粘杆菌素和基础日粮.于试验开始后第7、14和28 d每个处理随机选取5头试猪,前腔静脉采血,测定血常规和抗氧化指标.结果表明:刺五加提取物能显著改善断奶仔猪的抗病能力,减轻应激反应,机体抗氧化酶活性明显升高;第7 d时提取物组MID、PLT、MDA和NO含量显著小于基础日粮组(P＜0.05);第14 d时提取物组WBC显著小于、CAT活性显著大于基础日粮组(P＜0.05);第28 d时提取物组WBC、MID和GRA显著小于(P＜0.05),SOD活性大于基础日粮组(P＞0.05).     

菊粉和刺五加提取物对早期断奶仔猪生长性能、血液指标和肠道形态的影响

试验选用120头21日龄5.64kg左右的三元杂交断奶仔猪,分别饲喂基础日粮(对照组)、基础日粮+抗生素(抗生素组)和基础日粮+5%菊粉+0.1%刺五加提取物(实验组),试验期为14d,观察日粮中复合添加菊粉和刺五加(AS)提取物对早期断奶仔猪生长性能、血液生化指标和肠道形态的影响。试验结果表明,实验组与对照组相比,仔猪日增重(ADG)显著提高(P0.05),而料肉比(F/G)则显著降低(P0.05),但平均日采食量(ADFI)差异不显著(P0.05);实验组仔猪血清中血糖(GLU)、低密度脂蛋白(LDL)、乳酸脱氢酶(LDH)和尿素氮(BUN)与对照组差异不显著(P0.05),但试验第14d,碱性磷酸酶(ALP)、超氧化物歧化酶(SOD)和还原型谷胱甘肽(GSH)浓度均显著高于对照组(P0.05);实验组仔猪十二指肠和回肠的隐窝深度显著高于对照组(P0.05),空肠和回肠的绒毛高度显著高于对照组(P0.05)。试验显示,日粮中添加菊粉和刺五加提取物对提高早期断奶仔猪的生长性能、改善小肠消化和吸收功能有重要作用。     

微生态制剂对断奶仔兔生产性能及免疫的影响

目的研究微生态制剂对断奶仔兔生产性能、免疫功能的影响,为开发应用新型添加剂提供依据。方法选择64只35日龄、体重相近的断奶仔兔,随机分为4组,每组设2个重复,每个重复8只。实验期为40 d。对照组Ⅰ饲喂基础饲粮,实验组Ⅱ、Ⅲ、Ⅳ在基础日粮中分别添加0.1%、0.3%、0.5%的微生态制剂。测定日增重、饲料报酬、发病率、死亡率、胸腺指数、脾脏指数及T淋巴细胞ANAE阳性细胞百分率等指标。结果实验组Ⅱ、Ⅲ、Ⅳ日增重分别比对照组I提高了10.6%（P〈0.05）、23.967%、27.0%（P〈0.01）,饲料报酬分别提高了6.8%、14.3%、15.1%,发病率分别降低了12.5%、18.7%、18.7%,死亡率分别降低了12.5%、12.5%、18.7%,脾脏指数分别提高了11.5%（P〈0.05）、29.5%、34.4%（P〈0.01）,胸腺指数分别提高了2.3%、15.9%、17.9%,T淋巴细胞阳性率分别提高了17.7%（P〈0.05）、26.9%、28.4%（P〈0.01）。结论在断奶应激的情况下,饲料中添加微生态制剂可提高仔兔的生产性能和免疫功能。     

Maximal growth occurs at a broad range of essential amino acids to total nitrogen ratios in kittens

Summary Kittens fed diets containing 2.0 and 3.0 times (X) the NRC (1986) essential amino acid (EAA) requirement (EAArq) and 210 to 560g crude protein (CP)/kg diet had growth rates and plasma amino acid patterns that were not significantly different than kittens fed a control diet (CD) containing 1.5 X EAArq and 350 g CP/kg diet. Growth rates of kittens fed diets containing only EAA (with nontoxic levels of arginine and methionine) and 280 to 460 g CP/kg diet were equivalent to those of kittens fed CD. Kittens fed only EAA and 140 and 210 g CP/kg diet had growth rates that were significantly lower than kittens fed CD. Since the growth rate of kittens fed 1.5X EAArq and 210 g CP/kg diet in a previous experiment was equivalent to kittens fed CD (Taylor et al., 1997), it is suggested that the requirement for CP is higher (up to 280 g CP/kg diet) when only EAA are fed. The higher crude protein requirement appears to be primarily a consequence of the high obligatory nitrogen loss as urea (especially from arginine) incurred in the conversion of nitrogen from EAA to dispensable amino acids in the liver and secondarily because of a slow rate of catabolism of the EAA. A 3-dimensional plot of weight gains vs. CP levels and EAA to total nitrogen (E: T) ratios of kittens shows a broad range of CP levels and E: T ratios that support optimal growth in the kitten. It is suggested that similar patterns would occur in the chick, rat and other species if adverse effects caused by excesses of specific amino acids are avoided.Presented in part at the Biology '96 Meeting in Washington, DC [Taylor TP, Deberry J, Morris JG, Rogers QR (1996) Effects of dietary nitrogen level and essential amino acid: total nitrogen (E: T) ratio on kitten weight gain. FASEB J 10: A737 (abs. 4259)] and in part at the Proceedings of the Waltham International Symposium, Pet Nutrition and Health in the 21st Century, Orlando, Florida, USA [Rogers QR, Taylor TP, Morris JG (1997) Optimizing dietary amino acid patterns at various levels of crude protein for the cat. J Nutr (abs.) (in press).     

Effects of increasing crude protein concentrations on performance and carcass characteristics of growing and finishing steers and heifers

A 2 × 3 factorial design was utilized to ascertain the effects of three dietary crude protein (CP) concentrations on performance, carcass characteristics, and serum urea nitrogen (SUN) concentration in steers and heifers. Animals were blocked by gender (n = 9) and body weight (BW; n = 3/gender), randomly assigned to a diet containing 110, 125 or 140 g/kg dietary CP (n = 6), subjected to a growing period of 56, 84 or 112 d, depending on start BW, and a finishing period of 84 d. Animals were weighed and bled at 28 d intervals and daily dry matter intake (DMI), average daily gain (ADG), and gain to feed (G:F) were calculated and SUN was analyzed as a repeated measure throughout the study. Following slaughter, carcass data was collected for hot carcass weight (HCW), dressing percent (DP), kidney, pelvic and heart fat (KPH), 12th rib backfat (BF), loin muscle (LM) area, marbling score (MS), and yield grade (YG). Growing steers and heifers were programmed to gain 1.02 and 0.91 kg/d, respectively. Therefore, heifers consumed less than steers and steers gained more than heifers (P<0.01) with no differences in feed efficiency. Dietary CP treatment did not effect DMI, but did result in a quadratic (P=0.04) increase in ADG; thereby quadratically (P=0.06) and linearly (P=0.08) increasing final BW, and G:F, respectively. Finishing heifers consumed and gained less than steers (P<0.01), had lighter HCW (P<0.01) and greater DP (P=0.01) and LM area (P=0.01) than steers. DMI (P=0.02), ADG (P=0.05), HCW (P=0.08), and DP (P=0.06) reacted quadratically with increasing dietary CP. HCW (P=0.02) increased linearly with increasing dietary CP. G:F, KPH, BF, LM area, MS and YG was not affected by dietary CP concentration and G:F, KPH, BF, MS, and YG did not differ between genders. However, there was a gender × dietary CP interaction (P=0.01) for G:F. Steers were the most efficient at 125 g/kg dietary CP, while heifers were most efficient at 140 g/kg dietary CP. Gender had no effect on SUN concentrations, but SUN increased linearly (P<0.01) with increasing dietary CP concentrations. In conclusion, quadratic responses in DMI and ADG indicate that a 125 g/kg dietary CP concentration is optimal for either steers or heifers during the finishing period.     

Variation in faecal digestibility values related to feed efficiency traits of grower-finisher pigs

Providing pigs a diet that matches their nutrient requirements involves optimizing the diet based on the nutrient digestibility values of the considered feed ingredients. Feeding the same quantity of a diet to pigs with similar BW but with different requirements, however, can result in a different average daily gain (ADG) and backfat thickness (BF) between pigs. Digestibility may contribute to this variation in efficiency. We investigated variation in feed efficiency traits in grower-finisher pigs associated with variation in faecal digestibility values, independent of feed intake at the time of measuring faecal digestibility. Considered traits were ADG, average daily feed intake (ADFI), feed conversion ratio (FCR), BF and residual feed intake (RFI). Feed intake, BW, and BF data of one hundred and sixty three-way crossbreed grower-finisher pigs (eighty female and eighty male) were collected during two phases, from day 0 of the experiment (mean BW 23 kg) till day 56 (mean BW 70 kg) and from day 56 to slaughter (mean BW 121 kg). Pigs were either fed a diet based on corn/soybean meal or a more fibrous diet based on wheat/barley/by-products, with titanium dioxide as indigestible marker. Faecal samples of one hundred and five pigs were collected on the day before slaughter and used to determine apparent faecal digestibility of DM, ash, organic matter (OM), CP, crude fat (CFat), crude fibre (CF), and to calculate the digestibility of nonstarch polysaccharides (NSPs) and energy (E). The effects of diet, sex and covariate feed intake at sampling (FIs) on faecal digestibility values were estimated and were significant for all except for CFat. Faecal digestibility values of each individual pig determined at the day before slaughter, corrected for diet, sex and FIs, were used to estimate their association with ADG, ADFI, FCR, BF, and RFI. In the first phase, a one percent unit increase in faecal digestibility of DM, ash, OM, E, CP, CFat, CF, NSP, and Ash individually was related to 0.01–0.03 unit reduction in FCR and 6–23 g/day reduction in RFI. A unit increase in CP digestibility was related to 0.1 mm increase in BF and 10 g/day increase in ADG. In the second phase, a one percent unit increase in faecal digestibility of DM, CP and Ash was related to a decrease of 16–20 g/day in RFI. In conclusion, the relationship between variation in feed efficiency traits and faecal digestibility values is different across the developmental stages of a pig.     

Effects of feeding high- and low-fibre fractions of air-classified,solvent-extracted canola meal on diet nutrient digestibility and growth performance of weaned pigs

The dietary energy value of solvent-extracted canola meal (CM) is limited by its relative high fibre content. The fibre-rich hull of canola is denser than the oil-free cotyledons, so these seed components partially fractionate in a stream of air. Air classification thus separates CM into a low-fibre, light-particle fraction and a high-fibre, heavy-particle fraction of interest for feeding monogastric and ruminant species, respectively. Crude fibre (CF), acid detergent fibre (ADF) and neutral detergent fibre (NDF) in light-particle fraction were reduced by 96, 34 and 28% compared with CM (83 CF, 165 ADF, 238 NDF g/kg, as-is). Brassica (B) napus, Brassica juncea, or their fractions were evaluated feeding 288 weaned pigs (7.1 kg) for 37 d as a 2 × 3 factorial with 12 replicate pens per treatment. Wheat-based diets including 200 g of test feedstuff/kg provided 10.5 and 10.0 MJ net energy (NE)/kg and 1.27 and 1.15 g standardised ileal digestible lysine/MJ NE and were fed for 9 and 28 d, respectively. Pen feed added, orts, and individual pig body weight were measured weekly to calculate average daily feed intake (ADFI), average daily gain (ADG), and feed efficiency (G:F). Pen faecal samples were collected on d 16 and 17 to calculate diet apparent total tract digestibility coefficients (CATTD) of dry matter (DM), gross energy (GE), crude protein (CP) and digestible energy (DE) value. Pigs fed B. juncea had 3 and 2% higher (P<0.001) CATTD of DM (0.82 vs. 0.79) and GE (0.84 vs. 0.82) than pigs fed B. napus. Feeding the light-particle fraction increased (P<0.001) CATTD of DM (0.82 vs. 0.79), GE (0.84 vs. 0.82), and CP (0.79 vs. 0.77) by 4, 3 and 3% compared with CM, respectively. For the entire trial, pigs fed B. juncea consumed 33 g/d less (P<0.001) feed (723 vs. 756 g/d), had 0.02 higher (P<0.05) G:F (0.735 vs. 0.718 g:g), but ADG (503 vs. 514 g/d) was not different (P>0.05) compared to pigs fed B. napus. Feeding pigs the light-particle fractions did not affect (P>0.05) ADFI (741 vs. 736 g/d), increased (P<0.05) G:F 0.02 (0.739 vs. 0.721 g:g) and tended to increase (P=0.07) ADG (519 vs. 501 g/d) by 18 g/d compared to CM. In conclusion, air classification of canola meal increased diet nutrient digestibility, but only modestly increased G:F of weaned pigs due to dietary fibre reduction.     

Effect of feed restriction or feeding high-fibre diet during the rearing period on body composition, serum parameters and productive performance of rabbit does

This study evaluated the effect of different feeding regimes from 11 weeks of age to first parturition on feed intake, leptin, non-esterified fatty acids (NEFA) and total protein serum levels, as well as productive performance in young rabbit does. In addition, body composition was estimated by bioimpedance analysis. Thirty-six 11-week-old does were randomly distributed in three groups. The AL-C group was fed ad libitum a control diet containing 350 g neutral detergent fibre (aNDFom)/kg, 11.6 MJ digestible energy (DE)/kg and 173 g crude protein (CP)/kg, and the does were inseminated at 16 weeks of age. The R-C group was fed 150 g/d of the same diet until 16 weeks of age, one week before artificial insemination (AI) at 17 weeks of age, and then fed ad libitum. The AL-F group was fed a diet containing 475 g aNDFom/kg, 9.4 MJ DE/kg and 174 g CP/kg ad libitum, and was inseminated at 17 weeks of age. During rearing (11-16 weeks), does in the R-C group had the lowest DE (1.54 MJ/d; P<0.003) and digestible protein (DP, 17.9 g/d; P<0.001) intake, as well as the lowest protein (172 g/kg; P<0.05) and energy (5.9 MJ/kg) body contents, leptin concentration at 16 weeks of age (2.48 ng/ml; P<0.001) and fertility (P<0.02) at first AI. Daily feed intake during pregnancy and lactation, as well as prolificacy and litter weight, were similar among groups. The highest percentage of body fat was observed for all the does when were inseminated for the first time (135 g/kg; P<0.001), consistent with the highest leptin (4.48 ng/ml; P<0.001) and total protein serum levels (6.87 g/dl; P<0.001) at this time. Serum NEFA level around parturition was higher (P<0.05) in groups AL-C and R-C (1.11 and 0.85 mmol/l) than in group AL-F (0.71 mmol/l), suggesting a lower lipid mobilization that tended to improve fertility rate for AL-F does on day 11 post-parturition (P<0.09). In conclusion, feed restriction during the rearing period delays reproductive development in young rabbits. In nulliparous does, ad libitum feeding during rearing with a high-fibre diet allows a similar productive performance to that of feeding with a less fibrous diet. Nevertheless, the use of high fibre diets during rearing does not affect feed intake throughout the first pregnancy and lactation.     

Increasing dispensable amino acids in diets of kittens fed essential amino acids at or below their requirement increases the requirement for arginine

Summary Kittens fed diets containing 0.75 × the NRC (1986) essential amino acid requirement (EAArq) and 210 to 560g crude protein(CP)/kg diet exhibited, with increasing CP: 1) decreasing weight gain, 2) decreasing plasma arginine concentrations, 3) increasing urinary orotic acid excretion, 4) increasing plasma glutamic acid concentrations, and 5) plasma isoleucine concentrations at levels that suggest a marginal isoleucine deficiency. Kittens fed a control diet (CD) containing 1.5 × EAArq and 350 g CP/kg diet had maximal weight gains and no orotic aciduria. It was concluded that the decreased weight gain and adverse metabolic effects were caused by arginine deficiency and possibly glutamic acid toxicity induced by high dietary dispensable amino acids. Kittens fed the diets containing 1.0 × EAArq and 350 and 560 g CP/kg diet had depressed plasma arginine and elevated glutamic acid concentrations and orotic aciduria. These results indicate that 10 g arg/kg diet is not adequate at CP concentrations above 280 g/kg and the calculated requirement of arginine is (0.02 g arginine/g CP) × (Y g CP/kg diet) + (4.0 g arginine/kg diet) where Y is the dietary CP level.Abbreviations CD control diet - CP crude protein (g CP/kg diet = g nitrogen/kg diet × 6.25) - DAA dispensable amino acids - EAA essential amino acids - EAArq essential amino acid requirement     

Determination of polyphenol and crude nutrient content and nutrient digestibility of dried and ensiled white and red grape pomace cultivars

The present study aimed to determine the nutrient and energy content of fresh and ensiled grape pomace (GP) from different grape varieties originating from Germany, and to estimate the feed value of dried white, dried red and ensiled white GP by calculating nutrient digestibility and the content of metabolisable energy (ME) and net energy lactation (NEL) measured in sheep as a ruminant model. GP from red cultivars had higher contents of organic matter (OM), crude protein (CP), ether extract (EE), crude fibre (CF), total phenolic contents (TPC) and ME, whereas the concentrations of ash and sugar were lower than from white cultivars. Compared with untreated GP, ensiled GP had increased concentrations of CP (+19%), ether extract (EE; +23%) and CF (+12%) and a higher ME content (+7%) and markedly decreased concentrations of sugar (?99.6%) and TPC (?48%). The concentrations of dry matter, OM and ash were not different between ensiled and fresh GP. Compared with dried GP, ensiled GP had a higher nutrient digestibility (OM, +32%; CP, +43%; CF, +46%; neutral detergent fibre [NDF], +54%; acid detergent fibre [ADF], +69%) and higher energy values (ME, +16%; NEL, +19%). The digestibility of OM, CP, EE and CF and the energy content were higher for dried red than for dried white GP, whereas the digestibility of NDF_OM and ADF_OM was lower for dried red than dried white GP. In conclusion, the results show that both red and white GP are suitable dietary sources for enrichment with TPC. Furthermore, compared with drying ensiling of GP improves the feeding value of GP and is a good possibility of preserving the seasonally produced by-product of winemaking for ruminant feeding.     

Impaired translation initiation activation and reduced protein synthesis in weaned piglets fed a low-protein diet

Weanling mammals (including infants) often experience intestinal dysfunction when fed a high-protein diet. Recent work with the piglet (an animal model for studying human infant nutrition) shows that reducing protein intake can improve gut function during weaning but compromises the provision of essential amino acids (EAA) for muscle growth. The present study was conducted with weaned pigs to test the hypothesis that supplementing deficient EAA (Lys, Met, Thr, Trp, Leu, Ile and Val) to a low-protein diet may maintain the activation of translation initiation factors and adequate protein synthesis in tissues. Pigs were weaned at 21 days of age and fed diets containing 20.7, 16.7 or 12.7% crude protein (CP), with the low-CP diets supplemented with EAA to achieve the levels in the high-CP diet. On Day 14 of the trial, tissue protein synthesis was determined using the phenylalanine flooding dose method. Reducing dietary CP levels decreased protein synthesis in pancreas, liver, kidney and longissimus muscle. A low-CP diet reduced the phosphorylation of eukaryotic initiation factor (eIF) 4E-binding protein-1 (4E-BP1) in skeletal muscle and liver while increasing the formation of an inactive eIF4E.4E-BP1 complex in muscle. Dietary protein deficiency also decreased the phosphorylation of mammalian target of rapamycin (mTOR) and the formation of an active eIF4E.eIF4G complex in liver. These results demonstrate for the first time that chronic feeding of a low-CP diet suppresses protein synthesis in animals partly by inhibiting mTOR signaling. Additionally, our findings indicate that supplementing deficient EAA to low-protein diets is not highly effective in restoring protein synthesis or whole-body growth in piglets. We suggest that conditionally essential amino acids (e.g., glutamine and arginine) may be required to maintain the activation of translation initiation factors and optimal protein synthesis in neonates.     

The effect of exposure to oestrous ewes on rams' sexual behaviour, plasma testosterone concentration and ability to stimulate ovulation in seasonally anoestrous ewes

Ruminants eat a variety of foods from different locations in the environment. While water, cover, social interactions, and predators are all likely to influence choice of foraging location, differences in macronutrient content among forages may also cause ruminants to forage in different locations even during a meal. We hypothesized that lambs forage at locations containing foods that complement their basal diet and meet their nutritional needs. Based on this hypothesis, we predicted that lambs (n=12) fed a basal diet low in protein and high in energy would forage where a high-protein food (Food P) was located, and that lambs (n=12) fed a basal diet low in energy and high in protein would forage where a high-energy food (Food E) was located. Food P was a ground mixture of blood meal (50%), grape pomace (30%), and alfalfa (20%) that contained 47% crude protein (CP) and 2.211 Mcal/kg digestible energy (DE). Food E was a ground mixture of cornstarch (50%), grape pomace (30%), and rolled barley (20%) that contained 6% CP and 3.07 Mcal/kg DE. Food P provided 212 g CP/Mcal DE, whereas Food E provided 20 g CP/Mcal DE. Lambs growing at a moderate rate require 179 g CP and 3.95 Mcal DE. During Trial 1, we determined if lambs foraged to correct a nutrient imbalance, and if they preferred a variety of foods (Foods P and E) to only one food at a location (Food P or E). During Trial 2, we determined if nutrient-imbalanced lambs foraged in the location with the food that corrected the imbalance when the location of the foods changed daily. During Trial 3, lambs were offered familiar foods (Foods P and E) at the location furthest - and novel foods (wheat and soybean meal) at the location nearest - the shelter of their pen. During all three trials, lambs foraged most at the location with the food that contained the highest concentration of the macronutrient lacking in their basal diet, but they always ate some of both foods. Lambs did not feed exclusively at the location with a variety of foods (P and E). Rather, they fed at the location nearest the shelter that contained the macronutrient lacking in their diet. As availability of the food with the needed macronutrient declined in one location, lambs moved to the nearest location that had food with the needed macronutrient. When food that complemented their basal diet was moved to a different location, lambs foraged in the new location. Collectively, these results show that lambs challenged by imbalances in energy or protein selected foods and foraging locations that complemented the nutrient content of their macronutrient imbalanced basal diets.