仔猪早期断奶应激与营养调控

本文重点分析了早期断奶应激对仔猪消化生理的影响,并对几种主要营养调控措施进行了评述。     

早期断奶仔猪的谷氨酰胺营养

近２０年来，非必需氨基酸（NEAA）谷氨酰胺（Gln）因其独特而复杂的生理功能逐渐成为营养学及营养免疫学等学科领域的研究热点。谷氨酰胺在猪乳游离型或蛋白质结合型氨基酸中含量最丰富，断奶后肠细胞谷氨酰胺氧化速率的加快表明谷氨酰胺作为断奶仔猪肠细胞代谢的能量物质非常重要。在NRC（１９９８）《猪的营养需要》中，谷氨酰胺已经被定义为“条件性必需氨基酸”（NRC，１９９８）。１谷氨酰胺的营养生理功能谷氨酰胺最重要的生理功能是作为组织间转氨作用的载体。谷氨酰胺是体内蛋白质、辅酶I、嘧啶和嘌呤核苷酸以及氨基糖等合成…     

早期断奶仔猪的营养

为了提高经济效益，规模化猪场大多实行早期断奶．即在仔猪21-28日龄时断奶，同时给仔猪提供营养全面及经过强化的日粮。临城种猪公司饲养的法系大白、长白猪，早期断奶后经1周的强化饲养，平均体重均可达到9kg以上，除了法系猪本身优良的遗传潜力外，与科学全面的营养措施是分不开的。本文拟结合我公司的生产实践，讨论与早期断奶有关的营养措施。     

断奶仔猪的糖类营养及主要来源

早期断奶仔猪易受生理、营养和环境的影响，而产生应激影响其正常生长，其中营养因素最为重要，本文阐明了仔猪料中碳水化合物的作用厦其消化酶的分布特点。描述了仔猪时碳水化舍物的消化吸收机理，并时几种主要的碳水化合物来源和利用性能进行分析和总结，为合理配制断奶仔猪饲料提供理论基础。     

谷氨酰胺与早期断奶仔猪肠道营养免疫

仔猪早期断奶由于受到生理、营养和环境的突然改变，加上消化道发育不完善，引起“早期断奶综合征”，表现为采食量下降，生长受阻和腹泻。谷氨酰胺（Glutamine,Gin）是一种肠粘膜保护剂，外源添加可以缓解早期断奶仔猪应激引起的肠道结构和功能的改变，为养猪生产中的断奶仔猪腹泻问题提供有效的解决方法。     

断奶仔猪的糖类营养及主要来源

早期断奶仔猪易受生理、营养和环境的影响,而产生应激影响其正常生长,其中营养因素最为重要,本文阐明了仔猪料中碳水化合物的作用及其消化酶的分布特点,描述了仔猪对碳水化合物的消化吸收机理,并对几种主要的碳水化合物来源和利用性能进行分析和总结,为合理配制断奶仔猪饲料提供理论基础。     

减少仔猪早期断奶应激探讨

仔猪早期断奶是提高母猪生产性能的重要手 段之一,也是切断母猪疾病感染仔猪,减少仔猪疾病的有 效途径之一。但不同断奶日龄及营养水平对仔猪产生不同 程度的应激,直接影响仔猪断奶后的存活率和日增重,为 确保早期断奶技术的应用效果,应根据实际条件,尤其是 营养水平来确定适宜的断奶日龄。     

仔猪早期断奶及其饲养管理

仔猪早期断奶是在大规模集约化养猪生产中发展起来的一项全新的饲养管理技术，不仅可提高母猪的繁殖率和产仔数、分娩舍的利用率、提高饲料的利用率，而且可以有效地控制疾病。仔猪早期断奶是一项适合我国养猪业规模和经济状况的饲养技术。     

凡纳滨对虾营养生理和高效环保饲料研究进展

凡纳滨对虾(Penaeus vannamei)是我国最主要的海水对虾类养殖品种,2021年海水养殖产量达到119.77万吨,占全国海水虾类养殖总产量的80%以上。目前,国内外对于凡纳滨对虾的营养需求与饲料研究已有较多报道,但是对于不同生长阶段的精准营养需求以及营养素和功能性饲料添加剂的相互关系研究仍不够深入。本文主要就其蛋白质、脂肪、碳水化合物和微量营养素的需求,蛋白源和脂肪源替代鱼粉和鱼油,功能性饲料添加剂应用等方面的研究进展进行综述,以期为凡纳滨对虾的精准营养研究及高效环保饲料的开发提供科学参考,从而推动其养殖业的健康可持续发展。     

The minimum dietary lysine requirement,maintenance requirement and efficiency of lysine utilization for growth of Atlantic salmon smolts

This study was conducted to evaluate and refine the dietary lysine requirement of Atlantic salmon (Salmo salar) smolts using both the dose–response technique to determine the minimum dietary requirement and different ration levels to determine the maintenance lysine requirement and the efficiency of lysine utilization for growth. Diets containing 1.97–3.16% lysine (presented in protein‐bound form of lysine) were fed to satiation or at 25–75% ration levels to smolts during the last week in fresh water and the following 9 weeks in seawater. Based on the exponential lysine gain response to increasing dietary lysine concentrations, the minimum lysine requirement was found to be 2.67% of diet (dry matter basis; protein‐bound form or 3.05% free form). The smolts fed the unsupplemented diet maximally utilized the digestible lysine intake for growth. The efficiency of digestible lysine utilization for growth was 0.85 in the diet containing 2.88% lysine and the maintenance requirement was 21.7 mg digestible lysine kg^?0.7 day^?1.     

稚鳖赖氨酸营养的需要量

选择体重为(22.62±0.52)g稚鳖90只,平均分成6组,分别饲喂含赖氨酸为1.42、1.87、2.22、2.57、2.92和3.32%的等能等氮半合成饵料,试验期45d.结果表明,赖氨酸缺乏会降低鳖的生活力,导致其食欲下降、生长受阻、体蛋白沉积下降、肝生长受阻和赖氨酸-α-酮戊二酸还原酶活力下降(P＜0.01);赖氨酸对鳖的增重、饵料系数、体蛋白沉积量和净沉积率、体赖氨酸沉积量和净沉积率、肝重/体重和肝赖氨酸-α-酮戊二酸还原酶活力影响极显著(P＜0.01),并成极显著或显著二次回归关系(R2=0.7667-0.9594,P＜0.005～0.02).根据这些指标确定的赖氨酸需要量差异不明显,稚鳖赖氨酸需要量为2.40%或5.32g@(100gCP)-1.尽管赖氨酸对摄饵量和肝重也有极显著影响(P＜0.01),但是不呈显著二次回归关系(R2=0.3766-0.5990,P＞0.05).     

史氏鲟幼鲟对饲料中磷的需要量

通过生长饲养试验研究史氏鲟幼鲟对饲料中磷的需要量.以Ca(H2PO4)2·H2O为磷源,配制含磷水平分别为0.18%(对照组),0.40%,0.71%,0.98%,1.38%和1.66%的6组等能等氮纯化饲料,每组饲料饲喂3个重复,每个重复饲养20尾初体质量约为4.7 g的幼鲟.经过8周的饲养后,对生长、饲料效率、成活率、幼鲟肌肉常规组成及脊椎骨灰分和钙磷含量进行分析.结果表明,随饲料中磷含量的升高,鱼体增重率、饲料效率和特定生长率显著增加(P<0.05),直至0.98%组达最大,然后随着饲料磷含量的增加,这些指标显著降低(P<0.05);试验各添加组的成活率显著高于对照组(P<0.05),但各添加组间没有显著差异(P>0.05);饲料添加磷对鱼体肌肉水分、粗蛋白质和粗脂肪含量无显著影响(P>0.05);当饲料磷含量在0.71%～1.66%之间时,脊椎骨中灰分、钙和磷含量差异不显著(P>0.05),但显著高于对照组和0.40%试验组(P<0.05).经过折线回归分析得出,为维持史氏鲟幼鲟最佳生长和骨骼磷水平,饲料中磷的需要量为0.88%～1.00%(占干饲料).     

The effect of water-borne magnesium on the dietary magnesium requirement of the rainbow trout (Oncorhynchus mykiss)

Rainbow trout (Oncorhynchus mykiss) (mean initial weight 0.84 g) were fed diets containing graded levels of magnesium (Mg) (78 to 725µg/g) while being exposed to one of several levels in the rearing water (1.4 to 1000 mg/l). Uptake of Mg from the water, in Mg-deficient fish, was linearly related to the water Mg concentrated. It appears that the fish's Mg requirement can be met from either or both the diet or water. Under the experimental conditions, a water-borne concentration of 46 mg/l was calculated to be sufficient to meet the Mg requirement of the fish fed a Mg-free diet.     

梭鱼肌肉营养成分与品质的评价

利用常规营养测试方法对6尾梭鱼(雌雄各半)的营养成分进行了测定,并做了较为全面的分析和比较。结果表明,其肌肉鲜样中水分含量为80.90%,粗蛋白含量为17.25%,粗脂肪含量为0.76%,灰分含量为0.83%,碳水化合物为0.26%。肌肉中17种氨基酸的总量为干重的82.51%。其中,7种必需氨基酸的总量占干重的33.14%,占氨基酸总量的40.18%,必需氨基酸与非必需氨基酸的比例为78.40%,符合FAO/WHO的标准。梭鱼的第一、二限制性氨基酸分别为蛋氨酸+胱氨酸和缬氨酸,必需氨基酸指数(EAAI)为59.63。梭鱼肌肉中含有24种脂肪酸,不饱和脂肪酸含量丰富,与饱和脂肪酸的比例约为3:1;必需脂肪酸ω-6和ω-3家族的比例(6.11:1)合理;EPA+DHA的含量占干重的4.32%,高于其他一些经济鱼类。梭鱼微量元素的比例合理。     

Protein requirement of juvenile Manchurian trout Brachymystax lenok

SUMMARY: This study was conducted to determine the dietary protein requirement for the growth of juvenile Manchurian trout Brachymystax lenok . Three replicate groups of fish weighing 3.44 g were fed the five isocaloric diets containing various protein levels from 29% to 57% for 10 weeks. White fish meal was used as the sole protein source. Weight gain and feed efficiency of fish improved with increasing dietary protein level up to 43% and 49%, respectively, and reached a plateau above these levels. Dietary protein requirement using a broken-line model was estimated at 43.6% for weight gain of the fish. The protein efficiency ratio tended to decrease with increasing dietary protein level, but there was no significant difference among the diets containing 29%, 35% and 43% protein levels ( P > 0.05). The protein content of fish fed the 29% protein diet was significantly lower than that of fish fed the 57% protein diet ( P < 0.05). However, moisture, lipid and ash contents of fish were not significantly affected by dietary protein level ( P > 0.05). These findings indicate that 43–44% dietary protein level with 10% lipid and 19.2 MJ gross energy/kg diet could be recommended for the optimum growth and efficient protein utilization of juvenile Manchurian trout.     

Dietary protein requirement of juvenile marbled spinefoot rabbitfish Siganus rivulatus

Rabbitfish are an Indo‐Pacific herbivorous marine fish that have good market demand and are suitable for aquaculture. The present work was performed to determine dietary protein inclusion necessary for optimal growth of juvenile rabbitfish Siganus rivulatus. Six diets with increasing levels of protein (10, 20, 30, 40, 50 and 60 g crude protein 100 g^?1 feed) and similar levels of gross energy (20 MJ kg^?1) were prepared and offered to S. rivulatus juveniles maintained in triplicate cages placed in two large water tanks for 49 days. Growth progressively improved with dietary protein for fish offered diets from 10% to 40% protein inclusion. Diets with greater protein levels did not improve fish growth beyond that observed in the 40% group. Daily feed intake, apparent protein utilization and feed conversion ratio decreased as dietary protein increased. Protein efficiency (PE) was greatest (1.47) in fish offered the 10% protein diet and least in fish offered the 60% protein diet (0.80). No differences in PE were observed among all other treatments (20–50%). Results of the present work suggest that minimum dietary requirement for suitable growth of S. rivulatus juveniles is 40% protein when digestible energy of the diet is 16–18 MJ kg^?1.     

Dietary copper requirement of juvenile yellow catfish Pelteobagrus fulvidraco

The present experiment was conducted to quantify dietary copper (Cu) requirement for juvenile yellow catfish Pelteobagrus fulvidraco. The six experimental diets were formulated to contain the graded levels of CuSO₄·5H₂O (0, 0.005, 0.01, 0.02, 0.04 and 0.08 g kg^?1 diet respectively) providing the actual dietary copper values of 2.14 (control), 3.24, 4.57, 7.06, 12.22 and 22.25 mg Cu kg^?1 diet respectively. Each diet was fed to triplicate groups of yellow catfish (initial body weight: 3.13 ± 0.09 g, means ± SD) in an indoor static rearing system for 7 weeks. Fish fed the diet containing 3.24 mg Cu kg^?1 diet had the highest weight gain and specific growth rate, but they were not significantly different from that of fish fed the 4.57 and 7.06 mg Cu kg^?1 diets (P > 0.05). The poorest feed conversion rate, the lowest protein efficiency ratio, the lowest hepatosomatic index and viscerosomatic index were observed in fish fed the diet containing the highest Cu content diet (P < 0.05). Condition factor showed no significant differences among the treatments (P > 0.05). Proximate composition of fish body was significantly affected by dietary copper level (P < 0.05). Cu contents of whole body and liver increased with dietary Cu levels (P < 0.05), but muscle Cu content remained relatively stable (P > 0.05). Analysis by the second‐order regression of SGR and linear regression of whole‐body Cu retention of the fish indicated that dietary Cu requirements in juvenile yellow catfish were 3.13–4.24 mg Cu kg^?1 diet.     

Valine requirement of postlarval tiger shrimp, Penaeus monodon Fabricius

The valine requirement of juvenile tiger shrimp, Penaeus monodon Fabricius, was determined. Shrimp postlarvae, PL20, with a mean weight of 14 mg, were randomly distributed in 36 oval 40-L capacity fibreglass tanks at 10 shrimp per tank in a flow-through seawater system and reared for 8 weeks. Postlarvae were fed amino acid test diets containing 400 g kg^?1 protein with casein and gelatine as intact sources of protein. Crystalline L-amino acids were supplemented to simulate the amino acid profile of the shrimp muscle except valine. Valine was added in graded levels to obtain 7, 10, 13, 16, 19 and 22 g kg^?1 of the diet or 18, 25, 33, 40, 48 and 55 g kg^?1 of dietary protein. At termination of the feeding experiment, growth and survival were determined and nutritional deficiency signs noted. The relationship between weight gain and dietary valine level was analysed by the broken-line regression method to derive the valine requirement. The dietary valine requirement of Penaeus monodon postlarvae was found to be 13.5 g kg^?1 of the diet or 34 g kg^?1 of dietary protein. This value was lower than the level found in the shrimp tissue.