Correlated responses to selection for large body size in oMt1a-oGH mice: growth, feed efficiency and body composition

Correlated responses were determined for growth, feed consumption, feed efficiency and body composition following short‐term selection for large 8‐week body weight in transgenic and nontransgenic mice. Replicate lines which either carried or did not carry the sheep metallothionein 1a‐sheep growth hormone transgene (oMt1a‐oGH) were established. The lines carrying the transgene at an initial frequency of 0.5 came from a high‐growth (TM) and a randomly selected (TC) background. The respective nontransgenic lines were identified as NM and NC. Control replicates (CC) came from the randomly selected background. During the selection process the transgene was activated by adding 25 mm ZnSO₄ to the drinking water of all mice. Correlated responses were measured with (Z) and without (C) the addition of zinc. After seven and eight generations of selection, the frequency of transgenic mice in line TM had fallen sharply, whereas transgene frequency had risen moderately in TC. The reduced frequency of oMt1a‐oGH in the high‐growth genetic background may have been caused by a lower additive effect compared with the randomly selected background combined with a fitness disadvantage of the transgene. Therefore, the utility of a transgene in improving a quantitative trait may depend in part on genetic background. Correlated responses for most traits in NC were similar for Z and C. In contrast, correlated responses in TC showed marked differences in C compared with Z. For example, daily gain and feed efficiency showed no significantly correlated responses under C and positive responses (p < 0.001) under Z, and the reverse was found for indicators of body fat percentage. These line by environment (Z versus C) interactions may represent a genetic correlation of less than one between a trait expressed in two distinct environments. Thus, in developing lines with a transgene that can be regulated, a critical question is whether selection for quantitative trait(s) should be conducted when the transgene is activated or not activated.     

Genetic analysis of absolute growth measurements, relative growth rate and restricted selection indices in red Angus cattle

Performance records on 41,184 Red Angus cattle were analyzed and estimates of parameters calculated for absolute growth rate, relative growth rate and restricted selection indices. Heritability estimates for birth weight, 205-d weight, 365-d weight and postweaning gain were .46 +/- .02, .39 +/- .02, .40 +/- .02 and .36 +/- .02, respectively. Heritability estimates for preweaning, postweaning and postnatal relative growth rates were identical (.33 +/- .02). Heritability estimates for restricted selection indices were .31 +/- .02, .33 +/- .02 and .31 +/- .02 for weaning index, yearling index and postweaning index, respectively. The genetic correlation between preweaning and postweaning absolute growth rate was .15. The genetic correlation between consecutive measurements of relative growth rate (RGR) was -.33. Genetic correlations of birth weight with preweaning RGR and postnatal RGR were -.68 and -.71, respectively. Correlations among measures of relative growth rate using simulated data were similar to correlations of actual data, indicating that these relationships are the result of numerator/denominator relationships and not biological causes. The genetic correlation between weaning and postweaning indices was near zero. Small genetic coefficients of variation for preweaning and postnatal relative growth rates indicate further problems with the expression of growth in this manner. Restricted selection indices exhibited much larger genetic coefficients of variation than measurements of RGR. Genetic standard deviations were 7.8%, 7.2% and 13.7% of the means for weaning, yearling and postweaning indices, respectively.     

Correlated responses in body composition based on selection for different indicator traits in mice

Correlated responses in whole-body composition were determined in 12-wk-old male mice from replicate lines selected for 12 generations for high (HF) or low (LF) epididymal fat pad weight as a percentage of body weight (EPID) and high (HL) or low (LL) hind carcass weight as a percentage of body weight. The HF and LF lines diverged (P less than .01) in body fat percentage (FAT) and subcutaneous depot fat by 93 and 71%, respectively, of the control line (RC) mean. EPID increased (P less than .01) proportionately more than FAT in the HF line; EPID decreased (P less than .01) proportionately less than FAT in LF. Protein, fat and water as a percentage of empty body weight showed negative correlated responses (P less than .01) due to selection for EPID, but lean body mass, body weight and body length had positive correlated responses (P less than .01). Correlated responses of fat-free protein and ash percentage were minor. Correlated responses in HL and LL were the mirror images of those in HF and LF, but they generally were of smaller magnitude. The results indicate that, although there are high positive genetic correlations between fat depots in mice, local control of lipogenesis and(or) lipolysis exists at different sites of fat deposition. Further, the lack of correlated responses in fat-free percentage of protein (and percentage of ash) suggests that additive genetic variances are low for these traits and(or) the genetic correlations of these traits with the selection criteria are low.     

复合中草药对罗非鱼生长性能、免疫指标和体组成的影响

本试验采用单因素试验方法,研究复合中草药制剂对罗非鱼生长性能、免疫指标和体组成的影响。选用240尾罗非鱼苗,随机分为4个处理组,每个处理组3个重复,每个重复20尾。以基础饲料为对照组,试验组分别在基础料配方的基础上添加0.1%、0.2%、0.4%复合中草药制剂,饲养8周。结果表明:与对照组相比,0.1%和0.4%添加组增重率分别提高3.61%和4.09%,特定生长率均提高3.36%,饲料系数均降低4.5%(P<0.05);且适量中草药可降低转氨酶活性,提高罗非鱼粗蛋白质含量,降低粗脂肪含量。     

添加不同的促生长剂对鲤鱼生长和鱼体成分的影响

在基础日粮中分别添加 3 0 0 mg/ kg的二氢吡啶、1 0 0 mg/ kg的 DL-肉碱、4mg/ kg黄霉素、75 mg/ kg的喹乙醇以及 5 0 mg/ kg的复配抗菌素后 ,饲养初始重为 1 0 3 .1± 0 .9g的鲤鱼 ,经过 60 d生长试验 ,观察不同的添加剂对鲤鱼生长情况、机体营养成分组成的影响。结果表明 ,各添加剂对鲤鱼没有明显的促生长作用 ,但 DL-肉碱对降低全鱼的脂肪有一定作用     

Effect of selection for growth on normal and reduced protein diets on weight gain, feed intake, feed efficiency and body composition in mice

Mice selected for weight gain from 3 to 9 weeks of age on a normal (N) protein diet containing 19.3% protein and a reduced (R) protein diet with 5.1% protein were reared on both diets in generations 7 and 9. The lines NH, NC, NL, RH, RC and RL (H, high; C, control; L, low) were tested for weight gain on diet N and R and for feed intake and feed efficiency on diet N in generation 7. In generation 9, the lines were tested for body composition traits (fat, protein and water percentage) at 3, 6, 9 and 12 weeks of age on both diets. A significant (p < 0.0001) genotype × environment interaction for growth rate was observed in generation 7. Weight gain at both the protein levels was best improved by selection at the protein level itself. Furthermore, the ranking of the lines on diet N was similar for weight gain, feed intake and feed efficiency. In generation 9 at 9 weeks of age, the ranking of the lines for fat percentage was equal to the ranking for weight gain in generation 7 on both test‐diets. The association between weight gain and protein or water percentage was less pronounced, particularly on diet R. These results suggest that the largest genetic improvement in growth rate is obtained when the protein content of the feed is the same in selection and production. However, when selection is carried out in one environment while the animals have to perform under conditions with varying nutrient protein contents, selection in an inferior environment may be advantageous.     

不同水平复合蛋白源等量替代鱼粉对大口黑鲈生长性能、体成分组成以及肝脏生化指标的影响

为研究不同水平复合蛋白源在大口黑鲈配合饲料中等量替代鱼粉对大口黑鲈(micropterus salmoides)生长性能、体成分组成以及肝脏部分生化指标的影响,在基础饲料中用复合蛋白源分别等量替代0%、5%、10%、15%、20%、30%的鱼粉,配置成6种配方成本逐步下降的试验饲料,饲养初始体重约为100 g/尾的大口黑鲈60 d。结果显示:①大口黑鲈配合饲料中使用复合蛋白源等量替代鱼粉对大口黑鲈的存活率没有显著影响(P>0.05);各替代组的增重率、饲料系数与对照组均没有显著差异(P>0.05),其中以5%复合蛋白源等量替代鱼粉组的增重率最高,饲料系数最低。②随着饲料中复合蛋白源替代鱼粉水平的上升,大口黑鲈的肥满度呈现先升高后下降的趋势,其中以20%替代组的最高,但各组与对照组之间没有显著差异(P>0.05);不同含量复合蛋白源等量替代鱼粉各组的脏体比、肝体比与对照组之间没有显著差异(P>0.05)。③饲料中不同水平复合蛋白源等量替代鱼粉对各试验组大口黑鲈肌肉中的水分、灰分、粗脂肪、粗蛋白质、必需氨基酸、非必须氨基酸、单一氨基酸以及总氨基酸含量均没有显著影响(P>0.05)。④各试验组肝脏中超氧化物歧化酶(SOD)活性均高于对照组,其中30%含量替代组较对照组提高77.5%(P<0.05)。随着饲料中复合蛋白源替代鱼粉水平的上升,试验鱼肝脏的丙二醛(MDA)含量明显下降,当替代水平达到10%～30%时,肝脏的MDA含量显著低于对照组(P<0.05)。15%、20%、30%复合蛋白源等量替代鱼粉后的过氧化物酶(POD)活性分别较对照组提高72.2%、170.2%、69.6%(P<0.05)。各替代组的谷丙转氨酶(GPT)活性与对照组无显著差异(P>0.05),但谷草转氨酶(GOT)活性显著高于对照组(P<0.05)。上述结果表明,利用5%～30%的复合蛋白源等量替代大口黑鲈配合饲料中的鱼粉,对大口黑鲈的生长性能、体成分组成和氨基酸组成没有显著影响,但可以提高肝脏SOD、POD活性,降低肝脏MDA含量,同时也会提高肝脏谷草转氨酶活性。     

Genetic parameters and effect of selection for body weight in lines of mink (Neovison vison) on ad libitum and restricted feeding

Abstract

Selection was performed for high November weight on ad libitum (AL) and restricted feeding (RF) in mink in two generations. A farm fed line (FF) was maintained as a control. The estimates of heritability for November weight were large (0.62, 0.52, and 0.73 in males and 0.68, 0.51, and 0.60 in females in the FF-, AL-, and RF-line). The results indicate that selection on AL feeding increased appetite and thereby improved feed conversion ratio while selection on RF improved feed utilization. Furthermore, the results suggest that selection for August weight produces lean mink while selection for November weight produces fat mink.     

Genetic and physiological aspects of growth, body composition and feed efficiency in mice: a review

A review is presented of the genetic and physiological aspects of growth, body composition and feed efficiency in mice. The genetic parameters considered are: nature and extent of within and between-line genetic variation for body weight and growth rate; direct and correlated responses to selection for body weight, weight gain, feed intake and feed efficiency; direct genetic effects of the offspring (gO); maternal genetic effects (gM); heterosis in the offspring (hO); maternal heterosis (hM), and recombination effects in the offspring (rO). The physiological parameters considered are energy requirements for maintenance and growth. The role of thermoregulatory thermogenesis in relation to the partitioning of metabolizable energy between maintenance and growth requirements of large and small mice is emphasized. The relationship of feed efficiency with other traits is reviewed at length.     

Failure of photoperiod to alter body growth and carcass composition in beef steers

In each of two experiments, 70 crossbred steers were blocked by BW and assigned to initial slaughter groups or to treatments in a 2 x 2 design. In Exp. 1, treatments were 168 d of photoperiod (8 h of light [L]:16 h of dark [D] or 16L:8D) and plane of nutrition (high energy [HPN] or low energy [LPN]). On d -22, 67 and 155, blood was sampled every 20 min for 8 h. Relative to LPN, HPN increased (P less than .01) ADG by 28%, carcass weight by 26% and accretion of carcass fat by 109% and carcass protein by 20%. On d 155, compared with LPN, HPN increased (P less than .01) serum insulin (INS; 1.09 vs .64 ng/ml) and lowered (P less than .05) growth hormone (GH; 2.14 vs 3.70 ng/ml), but prolactin was not affected. Photoperiod did not affect BW gains, carcass composition or serum hormones. In Exp. 2, treatments were 113 d of photoperiod (8L:16D or 16L:8D) and Synovex-S implant (presence [IMP] or absence [NONIMP]). On d 93, blood was sampled every 30 min for 10 h. Relative to NONIMP, IMP increased (P less than .01) ADG by 12% and accretion of carcass protein by 16%. Implants did not affect carcass weight or accretion of fat. Compared with NONIMP, IMP increased (P less than .05) GH (3.16 vs 2.39 ng/ml) and INS (.68 vs .46 ng/ml) but did not affect PRL. Photoperiod did not affect BW gain, carcass composition or serum hormones. We conclude that photoperiod fails to influence growth and carcass composition of steers.     

Effects of growth rate and compensatory growth on body composition in lambs

Fifty lambs were used in a comparative slaughter experiment to determine the effects of growth rates and compensatory growth on body composition. The study consisted of a growing and a finishing phase. During the growing phase, lambs (20 to 30 kg) were fed three different concentrate levels (30, 50 or 70%) to gain at three different rates (slow, medium and rapid). The finishing phase was evaluated in two periods (early, 30 to 38 kg; late, 38 to 45 kg). All lambs received 70% concentrate diets during the finishing phase. Groups of five lambs were sacrificed at 20, 30, 38 and 45 kg fleece-free weights for whole-body chemical analysis. At 30 kg live weight, lambs on a rapid growth diet were the fattest (P less than .01) and contained the least protein (P less than .05) in their empty bodies. The slower the lambs gained during the growing phase, the greater (P less than .05) was the response in rate of gain and feed efficiency during both periods of the finishing phase. Compensatory growth occurred in two stages; a greater proportion of protein gain was made early while a greater proportion of the fat gain was made during the late period of the finishing phase.     

发酵牛粪作为饲料和肥料对主养鳙鱼生产性能的影响

由自制合理搭配的菌群发酵制得的牛粪为试验材料。一组(A池塘)为施无机肥和发酵牛粪,另一组(B池塘)为在养殖的过程中只施无机肥,养殖4个月。探讨发酵牛粪作为饲料和肥料对主养鳙鱼生产性能的影响。结果表明,牛粪发酵后,营养价值显著提高(P<0.05)。放养后,有机肥和无机肥结合的A池塘浮游生物量显著提高(P<0.05),A池塘养殖的鳙鱼、鲢鱼和鲤鱼的生长性能均显著高于B池塘(P<0.05)。在本试验条件下,发酵牛粪与无机肥联合使用可有效主养鳙鱼。     

枯草芽孢杆菌对中华绒螯蟹的生长性能和体成分的影响

挑选体重为(10.49±0.13)g健康的中华绒螯蟹180只,平均分成6组,每组3个重复,分别饲喂含0、0.25×109、0.5×109、1×109、2×109、4×109 cfu/kg枯草芽孢杆菌的饲料,进行8周的生长试验,以探讨芽孢杆菌对中华绒螯蟹生长性能及体成分的影响。试验结果表明,随着枯草芽孢杆菌添加量的增加,中华绒螯蟹的生长呈现先上升后下降的趋势,当饲料中添加1×109 cfu/kg时增重和特定生长率最大,且显著高于其他各组(P<0.05);通过方差分析,各个组全蟹的水分、粗脂肪、粗蛋白、粗灰分差异不显著(P>0.05);添加枯草芽孢杆菌试验组能降低肝体指数,1×109cfu/kg组的肝体指数最小,且显著小于对照组(P<0.05)。由此可见,饲料中添加适宜的枯草芽孢杆菌可显著提高中华绒螯蟹的生长,且不会明显改变全蟹的营养成分组成,适宜添加量为1×109 cfu/kg。     

Correlated responses in growth hormone to selection for weight gain in mice

SUMMARY: Correlated responses in pituitary gland weight and growth hormone (GH) concentration in the serum and pituitary were studied in lines of mice selected for growth rate, and in controls. The selection criteria were weight gain between 28 and 38 days on an ad libitum feed intake (EPA line), or on intake restricted to 80% of the control mice (EPR line), and weight gain between 48 and 58 days under the above two feeding regimes (LPA and LPR lines). The control line was maintained by random breeding. In generation 13, pituitary weight and growth hormone levels were determined at 38 days in lines EPA, EPR and the control and at 58 days in lines LPA, LPR and the control. Pituitary weight, corrected for body weight gain, was smaller in the EPA line than in the control line at 38 days and was greater in the LPR line than in the control line at 58 days. There were large differences in serum GH concentrations between the selected lines and the control; the differences were statistically significant at 38 days, with the EPA and EPR lines having lower levels than the controls. ZUSAMMENFASSUNG: Ver?nderung von Wachstumshormonspiegel bei Selektion für Zuwachs bei M?usen Ver?nderungen im Hypophysengewicht und Wachstumshormon-(GH)-Konzentrationen im Serum und in der Hypophyse wurden bei Wachstumsselektionslinien und bei Kontrollm?usen untersucht. Selektionskriterien waren Zuwachs zwischen 28 und 38 Tagen bei ad libitum Futteraufnahme (EPA Linie) oder bei Linien, wo Futteraufnahme auf 80% derjenigen der Kontrollm?use (EPR Linie) begrenzt wurde und Zuwachs zwischen 48 und 58 Tagen unter beiden Futterweisen (LPA und LPR Linie). Die Kontrollinie wurde durch Zufallspaarung fortgepflanzt. In Generation 13 wurden Hypophysengewicht und Wachstumshormonspiegel im Alter von 38 Tagen in Linien EPA, EPR und in Kontrollen und bei 58 Tagen in Linien LPA und LPR und Kontrollen bestimmt. Hypophysengewicht, korrigiert für Zuwachs, war geringer in der LPA Linie als in der Kontrolle bei 38 Tagen Alter und gr??er in der LPR Linie als in der Kontrolle bei 58 Tagen. Zwischen GH Konzentrationen selektierter und Kontrollinien waren erhebliche Differenzen, die bei 38 Tagen signifikant waren, wobei EPA und EPR Linien geringere Werte als die Kontrollen aufwiesen.     

不同处理方式豆角茎粉对罗非鱼生长性能、体成分及血液生化指标的影响

文章旨在评估通过浸泡和高压处理豆角茎粉对罗非鱼生长性能、体成分及血液生化指标的影响.试验将体重一致的864条罗非鱼随机分为4组,每组6个重复,每个重复36条.对照组罗非鱼饲喂不含豆角茎粉的日粮,T1～T3组分别饲喂25％未处理的豆角茎粉、25％浸泡豆角茎粉和25％高压处理豆角茎粉日粮.结果:对照组罗非鱼的末重、相对增重...     

Physiological change in camel milk composition (Camelus dromedarius) 1. Effect of lactation stage

The change in the composition of camel milk in four dromedaries was studied by including the common measured parameters: protein, total fat, lactose, main minerals (calcium, phosphorus, and iron), and vitamin C. The fat matter varied from 4.34% to 7.81% with a slight decrease all along the lactation and a minimal value at the 14th week corresponding to the lactation peak. Those variations were less important for protein content (from 2.58% to 3.64%), but the minimal value was observed at the 14th week also. The lactose varied slightly around its mean of 3.46%. The vitamin C concentration varied from 48 to 256 mg/l with a tendency of increasing all along the lactation. Calcium and phosphorus concentrations were quite parallel and their ratio Ca/P was constant. The minimal values (1.43 g/l for calcium and 1.16 g/l for phosphorus) were observed at the beginning of the lactation. The iron concentrations varied around the mean of 1.73 mg/l.