Relationships between body weight and other morphological traits in young sea cucumbers Apostichopus japonicas

Correlation, multiple regression, and path analyses were used to investigate the relationships between body weight and three other morphological traits in juvenile Japanese sea cucumbers Apostichopus japonicus . We measured live body weight (BW), body length (BL), numbers of papillae (NP), and numbers of tube feet (NF) at 60, 80, 100, and 130 days post-hatching (dph). We calculated path correlation coefficients, correlation indices ( R 2 ), and coefficients of determination with BW as the dependent variable and the other morphological traits as independent variables. The coefficient of variation for BW was high across all age groups, and all measured morphological traits were significantly correlated ( P < 0.01). BL had the greatest direct eff ect on BW across all age groups (60 dph, 0.526;80 dph, 0.404;100 dph, 0.620;and 130 dph, 0.681), while NF had the greatest indirect eff ect on BW across all age groups (60 dph, 0.528;80 dph, 0.452;100 dph, 0.666;and 130 dph, 0.603). Regression analyses between morphological traits and BW indicated that R 2 was greater than 0.85 only in the 100-dph specimens. The indirect eff ects of the other measured morphological traits on BW were age-dependent. The optimal regression equations, as determined with stepwise regression, were, for 60-dph specimens: BW 60 =10 (-3.04+0.092BL+0.014NP+0.014NF)( R 2 =0.632);for 80-dph specimens: BW 80 =10 (- 3.035+0.056BL+0.017NP+0.02NF)( R 2 =0.686);for 100-dph specimens: BW 100 =10 (- 3.742+0.069BL+0. 633 · lg (NP)+0. 464 · lg (NF))( R 2 =0.893);and for 130-dph specimens: BW 130 =10 (- 2.472+0.065BL+0.012NP)( R 2 =0.774). Our work clarified the correlation between various morphological traits and body weight of a commercially-important sea cucumber species ( A . japonicus ). Our predictive models for body weight might be useful for the aquaculture and selective breeding of A . japonicus . These models might also provide theoretical support for the indirect selection of traits that are difficult to select directly.

Heritability of resistance-related gene expression traits and their correlation with body size of clam Meretrix petechialis

Gene expression variation can be considered as a phenotype,and it plays an important role in both acclimation and adaption.However,genetic variation of gene expression received much less attention than traditional commercial traits in aquaculture.To estimate the genetic variation and heritability of gene transcription in clam Meretrix petechialis,five Vibrio resistance-related genes were selected for gene expression analysis in the digestive gland,and an animal linear model was used to analyze data from quantitative real-time PCR(qRT-PCR).Among the five genes,BIRC7 showed significant additive genetic variations,the heritability of this gene of 12-month-and 15-month-old clams were 0.84±0.32 and 0.91±0.34,respectively.The heritability of other four genes(Bax,NFIL3,Big-Def,and CTL9)expression were low-tomoderate but not significantly expressed.Additionally,no significant phenotypic and genetic correlations between the BIRC7 transcription trait and body size were detected.This study highlights that certain gene expression variation is heritable and provides a reference for indirect selection of M.petechialis with high Vibrio resistance.

Fluctuation of Body Size and Body Weight of Jinchuan Female Yak within One Year

To understand the exact changes in body size and body weight of Jinchuan female yaks within one year,the body size and body weight of 30 Jinchuan female yaks were measured from July 2015 to July 2016. The results showed that the body weight of Jinchuan female yak declined continuously since October 2015,and the weight loss in November 2015 was the largest. The body weight started to increase in May 2016,and the body weight increased significantly in June and July of 2016.

Structural Traits,Structural Indices and Body Weight Prediction of Arsi Cows

Structural measurements are indicators of animal performance,productivity and carcass characteristics.This study was conducted with the objectives of assessing structural measurements,developing body weight prediction and structural indices for cows of Arsi breed.The cows were purchased from highland and lowland agro-ecologies of Arsi and East Shoa zones of Oromia regional state,Ethiopia and kept in Adami Tulu Agricultural Research Center(ATARC)for the breed development purpose.Totally 222 cows were included in the structural traits measurement.Thirty four young heifers were also considered in the study.Twenty two structural traits were considered during observational survey.The structural index was calculated from the phenotypically correlated linear measurements.Structural traits were analyzed by T-test of SPSS version twenty four.The observed average values of height at wither,chest depth,heart girth,body length,pelvic width,cannon bone circumferences of the cows were 107,55.62,141.06,117.82,31.41 and 13.58cm,respectively.Heart girth(0.82),flank girth(0.73),hook circumferences(0.67),chest depth(0.65)and height at rump(0.64)were highly correlated(P<0.01)to body weight of the cows.Regression analysis indicated that hearth girth had the highest coefficient of determination for body weight of the cows and heifers.Accordingly,the simple linear equations were developed to predict the body weight of cows and heifers.Body weight of Arsi cow(y)=-221.005+3.1(heart girth)and Body weight of Arsi heifer(y)=-188.452+2.75(heart girth).Based on this,the measuring chart tape can be developed to estimate the body weight of Arsi cows and heifers at field condition where there is no access to weighing scales.

Correlation between Single Nucleotide Polymorphism Detection of Intron 1 of PRL Gene with Body Size Traits in Jingjiang Partridge Duck

[Objective]The research aimed to study the polymorphism of intron 1 and its effects on prolactin（PRL） gene and body size traits of Jingjiang Partridge Duck.[Method]Taking 96 Jingjiang partridge ducks as materials,the polymorphism of intron 1 of PRL gene was detected by PCR-RFLP method.And the relationship between the gene polymorphism and body size traits was analyzed.[Result]Intron 1 in PRL gene of Jingjiang Partridge Duck had sequence polymorphism.Two kinds of genotypes（AB and BB） were detected by DraⅠrestriction and genotype BB was dominant in population（91.67%）.The results of Chi-square test indicated that this site was in Hardy-Weinberg equilibrium in Jingjiang Duck（P 〉0.05）.The results of least square analysis showed that the ducks with AB genotype had larger pelvis breadth（P 〈0.01） but smaller chest measurement（P 〈0.05） than those of BB ducks.[Conclusion]It was preliminarily concluded that PRL gene could be regarded as useful candidate gene（marker） for part of body size traits of Jingjiang Partridge Duck and part of body size traits can be improved by allele selection.

Covariation in Insular Life-history Traits of the Rice Frog(Fejervarya limnocharis)in Eastern China

Although shifts in life-history traits of insular vertebrates, as compared with mainland populations, have been observed in many taxa, few studies have examined the relationships among individual life-history traits on islands. Lifehistory theory also predicts that there is a trade-off between body size and reproductive effort, and between egg size and clutch size. We surveyed the rice frog, Fejervarya limnocharis, on 20 islands within the Zhoushan Archipelago and two nearby sites on the mainland of China to compare differences in life-history traits and to explore relationships among those traits. Rice frog females reached a greater body size on half of the smaller islands among the total 20 surveyed islands, and larger egg size, decreased clutch size and reduced reproductive effort on most of the islands when compared to the two mainland sites. Insular body size was negatively correlated with reproductive effort. There was a negative correlation between egg size and clutch size. Results suggest that life-history theory provides a good explanation for co-variation between body size and reproductive effort, and between egg size and clutch size in rice frogs on the islands.

藏鸡杂交组合生长发育规律研究

研究旨在通过藏鸡杂交分析其生长发育规律,为藏鸡的杂交利用打好理论基础。以藏鸡纯系及其他2个地方鸡培育品系为素材,组成3个二元杂交组合和2个纯系组合,观测育雏期体重、公鸡7~13周龄体重、母鸡7~44周龄体重和13周龄公母鸡体尺、44周龄母鸡体尺,分析体重体尺相关性,探明藏鸡杂交鸡生长发育规律。结果显示:杂交组合各阶段公母鸡体重均明显大于藏鸡纯系(P<0.05),13周龄公母鸡体尺、44周龄母鸡体尺也明显大于藏鸡纯系(P<0.05)。各杂交组合公鸡体重体尺相关性较高,而母鸡则较低,综合分析表明,含藏鸡血缘的杂交鸡体重、体尺性状与藏鸡纯系相比均显著提高(P<0.05),其生长性能具有明显杂交优势。

长江三角洲白山羊不同杂交组合早期生长发育性状研究

为了研究长江三角洲白山羊不同杂交组合生长发育的差异,以长江三角洲白山羊为母本、以萨能奶山羊和波尔山羊为父本进行杂交选育,分析萨白F_(1)、波萨白F_(2)和长江三角洲白山羊F_(0)60日龄体重与体尺指标的变化。结果显示:波萨白F_(2)各日龄体重、平均日增重均显著高于长江三角洲白山羊F_(0)(P<0.05);波萨白F_(2)各日龄体重和平均日增重均高于萨白F_(1),萨白F_(1)各日龄体重和平均日增重均高于长江三角洲白山羊F_(0),但差异均不显著(P>0.05)。整个试验期间,波萨白F_(2)、萨白F_(1)各日龄体尺指标均高于长江三角洲白山羊F_(0),但差异均不显著(P>0.05);各组羊的体尺数据随着日龄的增加呈递增的趋势。该试验通过分析不同杂交组合羔羊体重、体尺等早期生长发育性状,为培育具有较高经济价值的长江三角洲白山羊肉用品种(系)提供了一定参考。

昆明犬幼犬生长发育规律研究

[目的]为揭示昆明犬幼犬的生长发育规律,进一步提升育种创新水平。[方法]选择24只8~27周龄昆明犬为试验对象,测定8个体尺指标(体高、体长、胸围、腹围、胸深、胸宽、荐高和管围)及体质量,并分析6个体尺指数(体长指数、胸围指数、胸宽指数、体躯指数、臀高指数和管围指数)与体尺、体质量间的Pearson相关性。[结果]随着周龄的增加,昆明犬幼犬体尺、体质量逐步升高,且公犬的生长速度总体要快于母犬;生长强度呈现出先高后低的趋势,在0~8周龄最高;绝对生长呈现出先升高后降低的规律,在12~14周龄最大。不同生长阶段幼犬的体尺指数变化幅度在4.26%~21.70%。除腹围与管围、胸宽、体高、胸深、荐高、体长的Pearson相关性不显著外,其他指标间均存在极显著相关性。其中,荐高与体高、体长的相关系数分别为0.979和0.880,体质量与8个体尺指标的相关系数为0.353~0.740,均达到极显著水平。[结论]昆明犬幼犬主要部位生长发育均衡;加强幼犬0~8周龄的饲养管理有利于挖掘其生长潜能;根据体尺、体质量间的相关性可精简测定指标、优化选育方案。

鲁中肉羊不同生长阶段体尺体重的遗传参数估计

估计鲁中肉羊不同生长阶段体尺、体重的遗传参数,分析各性状间的遗传规律,以期为鲁中肉羊育种规划工作提供理论依据。收集2015—2019年共15 040条鲁中肉羊体尺、体重数据,以初生、3月龄、6月龄、周岁和成年阶段的体重、体高、体长、胸围、胸宽、胸深、管围性状为研究对象,利用DMU软件中AI-REML结合EM算法并配合动物模型,以出生年份、出生季节和性别为固定效应,以加性效应和母体效应为随机效应,估计各性状的遗传力和遗传相关。结果表明,初生至成年阶段鲁中肉羊的体重的遗传力为0.18~0.51,体高的遗传力为0.15~0.60,体长的遗传力为0.09~0.42,胸围的遗传力为0.11~0.43,胸宽的遗传力为0.05~0.39,胸深的遗传力为0.06~0.21,管围的遗传力为0.11~0.59,初生至6月龄阶段母体遗传力为0.15~0.26,不同阶段性状间遗传相关系数-0.52~0.98,表型相关系数为-0.05~0.95,不同生长阶段间体重的遗传相关系数为-0.10~0.87,表型相关系数为0.01~0.91。综上,母体遗传效应对鲁中肉羊早期生长性状影响较大,随着成长母体遗传效应逐步减弱,周岁阶段体重遗传力在本研究中最高,不同生长阶段体尺体重间存在中到高的遗传相关,各生长阶段间6月龄与周岁阶段体重遗传相关系数最高。

复合酶制剂对哺乳期驴驹生长发育及营养物质消化代谢的影响

试验旨在探究复合酶制剂对驴驹生长发育、营养物质消化代谢的影响,为哺乳驴驹早期胃肠道机能、肠道健康及营养需要量的研究提供参考依据。选择出生日期与体重[(45.22±7.32)kg]相近,健康的2月龄哺乳母驴驹10头。随机分为对照组与试验组,每组各5头。在相同的饲养管理条件下,驴驹自由哺乳,自由采食玉米秸秆和苜蓿,补喂精料补充料。试验组驴驹在对照组驴驹饲喂的基础上补喂复合酶制剂(木聚糖酶15000 U/g,β-甘露聚糖酶400 U/g,β-葡聚糖酶10000 U/g,纤维素酶2000 U/g,蛋白酶1000 U/g,淀粉酶300000 U/g),补喂量为6.5 mg/(kg BW·d),进行为期60 d的补饲及营养物质消化代谢试验。结果显示:驴驹的体重、体尺无显著性变化,试验组驴驹体斜长和管围总增长较对照组分别提高了26.02%和2.17%(P>0.05);试验组驴驹干物质、有机物、酸性洗涤纤维、钙、磷和能量的采食量分别比对照组提高了2.99%、3.14%、6.67%、2.07%、1.11%和2.81%(P>0.05);试验组驴驹摄入能、粪能、沉积能、摄入氮、粪氮、沉积氮、氮代谢率、摄入钙、粪钙、沉积钙、钙代谢率、摄入磷、沉积磷和磷代谢率分别比对照组提高了2.81%、13.03%、4.46%、1.65%、10.09%、21.49%、19.54%、2.07%、3.47%、4.59%、2.32%、1.11%、39.06%和40.77%,尿能、尿氮、尿钙、粪磷和尿磷分别比对照组降低了78.10%、20.19%、33.33%、4.35%和9.81%,无显著性差异(P>0.05)。综上所述,在本研究条件下,给驴驹补喂酶制剂促进了驴驹体斜长和管围的增长,营养物质的采食量和代谢率有升高的趋势,但均未达到显著的效果。

铜锈环棱螺形态性状对体质量的影响分析

为探究铜锈环棱螺不同群体主要形态性状间的相关性及影响其体质量的主要因素,随机选取微山湖、东平湖、骆马湖、洪泽湖、长江江都区段和滇池的野生铜锈环棱螺,测量其壳高、壳宽、壳厚、壳口长、壳口宽及体质量,采用相关分析与通径分析方法,并建立体质量的最优多元回归方程。试验结果显示,壳厚与体质量相关性不显著,壳高、壳宽、壳口宽和壳口长均与体质量相关性极显著。6个群体的决定系数总和分别为0.916、0.927、0.794、0.886、0.810和0.783,表明已分析出影响体质量的大部分形态性状。铜锈环棱螺体质量性状的主要影响因素在6个群体中并不相同,其中壳高或壳宽对体质量的影响作用比较大,是铜锈环棱螺体质量的主要影响因素。经多元回归方差分析和偏回归系数显著性检验,偏回归系数极显著(P<0.01)。本试验结果可为铜锈环棱螺的品种选育提供参考依据。

8个地方鸡品种的体尺、屠宰性能及肉品质的比较及综合评价

【目的】通过比较分析贵州省8个地方鸡品种的体尺、屠宰性能及肉品质性状差异,为贵州地方鸡种的保护开发和利用提供基础数据。【方法】采用常规方法对乌蒙乌骨鸡、威宁鸡、普定高脚鸡、兴义矮脚鸡、黔东南小香鸡、赤水乌骨鸡、长顺绿壳蛋鸡和瑶山鸡的体尺指标、屠宰性能和肉品质性状指标进行测定,利用主成分分析法构建肉用性状综合评价模型。【结果】贵州8个地方鸡品种体尺性状、屠宰性能及肉品质指标存在明显差异,但屠宰率均大于86%,全净膛率均大于67%,8个品种均表现出了较佳的产肉性能;成功构建了肉用鸡综合评价模型,评分结果为:威宁鸡>乌蒙乌骨鸡>普定高脚鸡>赤水乌骨鸡>瑶山鸡>兴义矮脚鸡>黔东南小香鸡>长顺绿壳蛋鸡。【结论】8个地方鸡品种均表现出了良好的产肉性,是优质的肉鸡种质资源;综合评价结果显示,威宁鸡和乌蒙乌骨鸡肉用性能比较出色。

嘉积鸭母鸭体尺性状与瘦肉重的相关分析

为对嘉积鸭瘦肉重进行有效选择,研究测定了71日龄嘉积鸭体尺性状,运用SPSS 26.0软件分析体尺性状与瘦肉重间的相关性及其对瘦肉重的影响,建立了体尺性状与瘦肉重的最优回归模型。结果显示:瘦肉重(Y)与龙骨长(X_(3))极显著正相关(r=0.394,P<0.01),与胸深(X_(4))显著正相关(r=0.276,P<0.05);龙骨长、胸深、半潜水长(X_(2))是影响71日龄嘉积鸭瘦肉重的重要指标,其中龙骨长对瘦肉重的直接影响最大,为0.649,胸深和半潜水长对瘦肉重的直接影响分别为0.386和0.283;71日龄嘉积鸭体尺对瘦肉重的最优回归模型为:Y=-680.197+33.651X_(3)+27.744X_(4)+8.531X_(2)。综上所述,71日龄嘉积鸭瘦肉重与龙骨长、胸深和半潜水长密切相关,可通过建立的最优回归方程实现对瘦肉重进行间接选择。

饲粮粗蛋白水平对1~6周龄盐津乌骨鸡体重和体尺性状的影响

试验旨在研究饲粮粗蛋白水平对1~6周龄盐津乌骨鸡体重和体尺性状的影响。选取1日龄健康、体重相近的盐津乌骨鸡120只,随机分为3组,每组5个重复,每个重复8只鸡,分别饲喂粗蛋白水平为18.59%、20.09%和21.37%的试验饲粮。试验期6周。结果表明,1周龄时,21.37%组体重极显著高于18.59%组、20.09%组(P<0.01);3周龄时,20.09%组、21.37%组体重显著高于18.59%组(P<0.05)。饲粮粗蛋白水平对1周龄盐津乌骨鸡的平均日增重、料重比具有极显著影响(P<0.01),对3周龄平均日增重具有显著影响(P<0.05)。21.37%组1周龄体斜长、龙骨长、胫长、体高显著或极显著低于18.59%组(P<0.05或P<0.01);20.09%组2周龄胸宽显著高于18.59%组(P<0.05);21.37%组3周龄体斜长、胸深显著或极显著高于18.59%组(P<0.05或P<0.01);21.37%组4周龄胸宽显著高于18.59%组(P<0.05);21.37%组5周龄体斜长、龙骨长、副翼羽长显著高于18.59%组(P<0.05)。在6周龄时,18.59%组盐津乌骨鸡体重与体尺性状、羽毛性状的相关程度为胫长>体斜长>龙骨长>盆骨宽>主翼羽数>胸深>副翼羽长>体高>主翼羽长>胫围>胸宽(R=-0.004~0.885);20.09%组盐津乌骨鸡体重与体尺性状、羽毛性状的相关程度为体高>胸深>副翼羽长>龙骨长>主翼羽数>胸宽>体斜长>胫围>胫长>盆骨宽>主翼羽长(R=0.326~0.805);21.37%组盐津乌骨鸡体重与体尺性状、羽毛性状的相关程度为体斜长>胸深>胫围>胸宽>龙骨长>盆骨宽>体高>副翼羽长>主翼羽长>胫长>主翼羽数(R=-0.051~0.873)。研究表明,饲粮粗蛋白水平为21.37%时,1~6周龄盐津乌骨鸡的生长发育性能较好;饲粮粗蛋白水平为20.09%时,6周龄体重与体尺性状、羽毛性状指标相关性较好。

黄郎鸡体重增长曲线拟合度及体重与体尺的相关性分析

试验研究黄郎鸡的体重增长规律及体重和体尺性状间的关联。试验选取170只同批次健康状况良好的1日龄黄郎鸡(公:80只,母:90只),测定并记录0~23周龄的体重、13周龄的体尺,采用Logistic、Gompertz以及Von Bertalanffy三种非线性数学模型对0~23周龄不同性别的黄郎鸡体重数据进行拟合分析,同时对13周龄黄郎鸡公母之间的体尺性状进行比较,并分析体重与体尺之间的相关性。结果表明:拟合黄郎鸡生长曲线效果最佳的模型是Gompertz模型,拟合度(公:R^(2)=0.998,母:R^(2)=0.998),拐点周龄(公:7.93周,母:8.43周),拐点体重(公:612.49 g,母:540.56 g),最大周增重(公:104.12 g,母:81.08 g)。黄郎鸡公鸡的体重与体斜长、龙骨长、胫长、胫围、胸深、胸宽、骨盆均成极显著正相关(P<0.01),母鸡的体重与体斜长、龙骨长、胫长、胫围、胸深、胸宽、骨盆、胸角之间均呈极显著正相关(P<0.01)。本研究揭示了黄郎鸡生长发育规律、体重与体尺性状间的相关性,为黄郎鸡生产管理、阶段划分和育种性状指标选择提供了理论参考依据。

康县太平鸡体尺性状与屠宰性状的测定及相关性分析

为探究康县太平鸡的体尺性状、屠宰性状及两者间的相关性,以40周龄的健康太平鸡为研究对象,测定其体尺性状与屠宰性状,并对所有测定性状指标间的相关性进行分析。结果表明:40周龄太平鸡体斜长为21.87 cm、龙骨长为10.70 cm、胫长为9.01 cm、胫围为4.32 cm、胸围为28.05cm、胸深为10.65 cm、胸宽为6.82 cm、骨盆宽为7.65 cm;宰前活重为1920.7 g、屠体重为1712.5g、半净膛重为1533.4 g、全净膛重为1314.3 g、胸肌重为277.6 g、腿肌重为395.5 g、屠宰率为89.1%、半净膛率为79.3%、全净膛率为67.8%、胸肌率为20.8%、腿肌率为27.1%、心重率12.2%、腹脂率3.0%。太平鸡体斜长、胸围、胫长、胫围与屠体重、全净膛重、半净膛重、腿肌重之间呈极显著正相关(P<0.01)。结论:太平鸡产肉性能好、低脂,体斜长、胸围、胫长、胫围可以作为太平鸡屠宰性能选育的指标。

羌山云朵鸡体重·体尺指标与屠宰性状的相关性分析

为研究羌山云朵鸡的体重、体尺指标和屠宰性状间的相关性,对21周龄羌山云朵鸡的体重、体尺指标、屠宰性状进行了测定,并进行了相关性分析。结果表明:羌山云朵鸡公鸡的平均屠宰率为89.23%,平均全净膛率为73.27%,说明羌山云朵鸡的肉用性能良好;相关性分析结果表明,体重、体尺指标和屠宰性状部分指标间存在显著或极显著相关;公鸡的体重、体尺指标均显著高于母鸡(P<0.05)。

膨腹海马不同生长阶段的形态特征研究

【目的】探究膨腹海马(Hippocampus abdominalis)不同生长阶段特殊表型性状及其相关性,筛选出影响2月龄膨腹海马体质量的主要形态性状,为辅助膨腹海马形态学研究及其人工选育打下理论基础。【方法】以人工繁育的10日龄和2月龄膨腹海马为研究对象,根据需要分别测定下颌长(X1)、上颌长(X2)、吻长(X3)、眼径(X4)、眼后头长(X_(5))、头长(X_(6))、躯干长(X_(7))、尾长(X_(8))、背鳍长(X_(9))、体长(X_(10))及体质量(Y)等表型性状,运用相关分析、主成分分析比较10日龄和2月龄膨腹海马各表型性状间的相关性及主要发育方向,并以通径分析和灰色关联度分析探究2月龄膨腹海马主要形态性状对体质量的影响。【结果】除了10日龄膨腹海马的下颌长与背鳍长间的相关性不显著(P>0.05)外,2个时期其他性状间的相关系数均达显著(P<0.05)或极显著(P<0.01,下同)水平。不同生长阶段膨腹海马主成分聚焦的方向不同,10日龄到2月龄,膨腹海马初始体长增长较快,头吻部生长发育明显,后期则聚焦于躯干部的生长。通径分析结果显示,影响2月龄膨腹海马体质量的主要形态性状是头长和体长,其中体长对体质量的直接影响最大(0.763),而头长主要通过体长间接影响体质量(0.278);构建的回归方程(Y=-1.817+0.038X_(6)+0.029X_(10))可准确预测体质量的变化(F=127.556,P<0.01)。灰色关联度分析结果显示,与2月龄膨腹海马体质量关联度较高的形态性状包括躯干长、尾长、头长和体长,对应的关联系数分别为0.787、0.754、0.745和0.724。不同分析方法得出的结果略有差异,但与体质量关联度较高的形态性状中均含有体长。【结论】10日龄到2月龄膨腹海马的生长从头吻部转移到躯干生长。在以体质量为目标性状选育2月龄膨腹海马时,应以体长为主要选择性状,并兼顾头长、躯干长和尾长的协同选择。

固始鸡A系与矮小贵妃鸡杂交F_(1)代生长性能探究及生长曲线拟合

试验旨在探究固始鸡A系与矮小贵妃鸡杂交后代的生长发育规律,选育出最优杂交组合。试验以固始鸡A系和矮小贵妃鸡进行正反交后代为素材,每周测量体重,90日龄和110日龄分别测量体尺性状并进行相关性分析,使用Logistic、Gompertz和Von-Bertalanffy三种模型拟合其生长曲线。结果显示,前4周,AG公母鸡与GA公母鸡的生长速度差异不大,4周龄以后,生长速度出现差异分化,GA公鸡的拐点周龄为8周,AG公鸡的拐点周龄为7.2周。GA母鸡的拐点周龄为7.9周,AG母鸡的拐点周龄为6.7周。90日龄时,GA母鸡的体重、体斜长、胫长、胸深优于AG母鸡,110日龄时,GA公鸡的体斜长优于AG公鸡,与AG群体相比,GA群体体尺性状较为优良。GA群体体重与体斜长和骨盆宽存在显著相关(P<0.05)。Gompertz模型对AG公鸡与GA母鸡这两个群体拟合效果更佳,Logistic曲线对AG母鸡和GA公鸡这两个群体拟合效果更佳。综上所述,矮小贵妃鸡♂×固始鸡A系♀为最优杂交组合。