Genetic analysis for developmental behavior of some seed quality traits in Upland cotton (Gossypum hirsutum L.)

Analysis of genetic main effects andGE interaction effects for oil index(OID), protein index (PID), and lysineindex (LID) of Upland cotton (Gossypium hirsutum L.) were conducted for2-yr diallel cross data by using a seedgenetic model. Analysis approaches ofunconditional and conditional variances andcorrelations were employed to evaluatedevelopmental behavior of cottonseed. Thephenotypic means were relatively larger forF₂ generation than F₁ generation,and larger for all generations in 1993 thanin 1994. The results of variance analysisindicated that OID, PID, and LID weresimultaneously controlled by seed nuclear,cytoplasm, and maternal nuclear effects.Genetic effects due to maternal nuclearwere relatively more important at wholedevelopmental period. GE interactioneffects were the main contribution to thetotal variation of OID at first two stages,of PID at the forth stage, and of LIDacross all four stages, respectively. Notonly the phenotypic correlationcoefficients but also the coefficients dueto different genetic effects variedsignificantly between traits themselves atvarious stages. Different genetic effectscaused the variation of the correlationshipbetween traits themselves at various stages.     

Half-sib family selection for yield of digestible organic matter in kale (Brassica oleraceal L.)

Summary Four generations of half-sib family selection for yield of digestible organic matter have been completed, from an initial population which included marrow-stem kales, thousand-head kales, curled kales, Brussels sprouts and cabbages. Relative to the mean yields of two control cultivars the population means were: 106% (gen₀), 122% (gen₁), 128% (gen₂), 111% (gen₃) and 103% (gen₄). These initially encouraging and then disappointing results are discussed along with suggestions for improvements in the population improvement scheme, particularly with respect to the assessment of genotype-environment interactions.     

Variation in lysine,threonine, and tryptophan availability in meat and bone meal as estimated by the slope‐ratio growth assay technique in growing rats

Meat and bone meal (MBM) is an important protein source used in animal feeds. However, as the composition and availability of amino acids (AAs) in MBM fluctuate markedly, it is important to verify the magnitude of these parameters in different MBMs. In this study, the AA compositions of 19 MBMs were analyzed to confirm variations in lysine (Lys), threonine (Thr), and tryptophan (Trp), then which were compared with those of soybean meal (SBM) and fish meal (FM). Instability in Lys, Thr, and Trp availabilities in six MBMs were also considered after estimation using the slope‐ratio growth assay technique in rats. Variations in AA composition were evaluated using the coefficient of variance (CV: Standard deviation/Mean). CVs for Lys, Thr, and Trp content were 9.40, 11.83, and 18.12 in MBM, 2.71, 2.48, and 3.19 in SBM, and 10.09, 10.44, and 13.47 in FM. Furthermore, means and SDs for Lys, Thr, and Trp availabilities in MBM were 53.3 ± 10.4% (CV: 19.5), 65.9 ± 17.6% (CV: 26.6), and 83.2 ± 11.2% (CV: 13.5), respectively. These results provide the first evidence that variations in MBM AA compositions were 3.5 to 5.7 times higher than those in SBM, but similar to FM, and that the large variation in availability substantially existed.     

Quantitative l-lysine requirement of juvenile grouper Epinephelus coioides

An 8‐week feeding trial was conducted to determine the quantitative lysine requirement of juvenile grouper Epinephelus coioides (initial mean weight: 15.84 ± 0.23 g, mean ± SD) in eighteen 500‐L indoors flow‐through circular fibreglass tanks provided with sand‐filtered aerated seawater by feeding diets containing six levels of l ‐lysine ranging from 19.2 to 39.5 g kg^?1 dry diet in 4 g kg^?1 increments. The diets, in which 250 g crude protein kg^?1 diet came from fish meal and soybean protein concentrate, and 230 g kg^?1 from crystalline amino acids, were formulated to simulate the amino acid profile of 480 g kg^?1 whole chicken egg protein except for lysine. Each diet was assigned to three tanks in a completely randomized design. Grouper were fed to apparent satiation twice daily during the week and once daily on weekends. Weight gain and specific growth rate increased with increasing levels of dietary lysine up to 27.2 g kg^?1 (P < 0.05) and remained nearly the same thereafter (P > 0.05). Feed efficiency was the poorest for fish fed the lowest lysine diet (P < 0.05) and showed no significant differences among other treatments (P > 0.05). Survival could not be related to dietary treatments. Body composition remained relatively constant except for lipid contents in muscle and liver. Total essential amino acid contents in liver increased with dietary lysine level although there was a slight decline for fish fed the highest lysine level of diet. Plasma protein content increased with increasing dietary lysine level (P < 0.05), but cholesterol, triacylglycerol and glucose contents were more variable and could not be related to dietary treatments. Dietary lysine level significantly influenced morphometrical parameters (condition factor, hepatosomatic index and intraperitoneal fat ratio) of juvenile grouper (P > 0.05). Broken‐line analysis of weight gain indicated the dietary lysine requirement of juvenile grouper to be 28.3 g kg^?1 diet or 55.6 g kg^?1 dietary protein.     

论理想AA模式在蛋鸡营养中的应用

为准确评定和满足动物营养需要,降低饲料成本,减少排泄物对环境的污染,利用可消化AA平衡模式配制饲料越来越得到更多的认可。本文回顾了理想AA模式在蛋鸡上的应用、研究进展及影响因素,并总结了理想AA平衡模式在蛋鸡应用过程中亟待解决的问题。     

棉籽蛋白质饲料猪消化能估测模型的研究

本试验旨在通过研究棉籽蛋白质饲料中的营养物质(NM)和非营养物质(NNM)对其消化能值的影响,探讨通过棉籽蛋白质饲料的化学成分估测其猪消化能值的可行性,为建立棉籽蛋白质饲料猪消化能估测模型提供科学方法。选取体重(35±2)kg、遗传基础接近、健康良好的杜×长×大三元杂交去势公猪8头,采用2个4×4拉丁方试验设计,用全收粪套算法测定8种棉籽蛋白质饲料的消化能(DE),通过分析饲料中CP、EE、CF、Ash、NDF、ADF、ADL、GE与DE的相关关系及对DE变异的影响筛选出用于估测棉籽蛋白质饲料DE的最佳估测因子及估测模型。结果表明,棉籽蛋白质饲料的EE、CP、Ash与DE无显著的相关关系(︱r︱≤0.51,P>0.05),而CF、NDF、ADF、ADL、GE与DE呈高度的相关(︱r︱≥0.9 5,P<0.0 1),但CF、NDF、ADL和GE对DE的影响主要是通过ADF对DE的影响来实现的,因此,估测棉籽蛋白质饲料DE的最佳回归模型为DE(MJ/kg)=1 6.5 2-0.2 8×ADF%(R2=0.95,RSD=0.51,P<0.01)。该模型具有较高的估测精度、最少的估测因子和较强的可操作性。     

过瘤胃赖氨酸对奶牛产乳量及乳成分的影响

试验采用随机分组试验设计,选择健康的中国荷斯坦奶牛48头,按照胎次、产奶量、泌乳日期一致原则,均匀分成4组,试验各组基础日粮相同,就饲粮中添加过瘤胃赖氨酸对乳牛产乳量及乳成分的影响进行研究。4个处理组分别为：对照组（0添加组）不添加过瘤胃赖氨酸（RPLys）、试验Ⅰ组添加10g/（头·d）、试验Ⅱ组添加20g/（头·d）和试验Ⅲ组添加30g/（头·d）。试验结果显示：经过饲喂后,试验各组与对照组相比,产奶量显著提高;试验Ⅲ组和试验Ⅱ组都与对照组差异显著（P〈0.05）,其中试验Ⅲ组与对照组差异极显著（P〈0.01）;乳蛋白含量有所提高,其中试验Ⅲ组与对照组有显著差异（P〈0.05）;其他乳成分指标略有提高,但差异不显著（P〉0.05）。     

生长育肥猪可消化赖氨酸适宜需要量试验研究*

 采用实用饲粮，研究不同赖氨酸补加水平对20～60kg，60～90kg长×撒杂交猪（48♂，48♀）生产性能、血液理化指标和胴体品质的影响。同时用3头回—直肠吻合术猪分别测定生长期（20～60kg）和育肥期（60～90kg）猪基础饲粮中氨基酸消化率。结果表明，在生长猪饲粮（实测赖氨酸0.523%）和育肥期饲粮（实测赖氨酸0.415%）中补加赖氨酸，使其总赖氨酸水平分别达到0.75%和0.565%时，显著改善试猪生长性能，提高饲料利用率，血清尿素氮、甘油三酯和极低密度脂蛋白变化显著，但不影响胴体品质。试猪基础饲粮回肠表观氨基酸消化率和真消化率测定结果分别为：生长猪（20～60kg）：表观赖氨酸消化率80.7%，真赖氨酸消化率85.7%；育肥猪（60～90kg）：75.4%，80.4%。综合饲养试验和赖氨酸消化率测定结果求得生长育肥猪表观和真可消化赖氨酸适宜需要量依次为：生长猪（20～60kg）：0.649%，0.675%；育肥猪（60～90kg）：0.463%，0.484%。若以回肠真可消化氨基酸为基础，采用Lys/DE表示，生长期（20～60kg）：0.49g/MJ DE，0.51g/MJ DE；育肥期（60～90kg）：0.35g/DE，0.36g/DE。此时，其赖氨酸∶含硫氨基酸∶苏氨酸∶色氨酸模式分别为：100∶60∶65∶18；100∶65∶71∶21。