饲粮能量水平对42 d繁殖模式下獭兔繁殖性能、体重变化及血清生化指标的影响

本试验旨在探讨饲粮能量水平对42 d繁殖模式下獭兔繁殖性能、体重变化及血清生化指标的影响.试验选用平均体重为(3.56±0.17) kg的经产獭兔150只,随机分成3组,每组50个重复,每个重复1只.采用42 d繁殖模式,分别饲喂消化能水平为9.2、9.7和10.2 MJ/kg的试验饲粮.试验连续进行3胎.结果表明:1)饲粮能量水平极显著影响母兔泌乳力(P=0.0062)、第1胎产后体重(P=0.002 1)和仔兔断奶窝重(P=0.000 6);显著影响第1胎(P=0.047 5)和第3胎(P=0.030 2)母兔泌乳期第21天体重.2)饲粮能量水平极显著影响血清肌酸激酶(P=0.001 5)活性和甘油三酯(P=0.001 3)含量,显著影响高密度脂蛋白胆固醇(P=0.036 8)、总胆固醇(P=0.047 6)和胰岛素含量(P=0.015 9),对其他血清生化指标无显著影响(P＞0.05).由此可见,42 d繁殖模式下獭兔适宜饲粮消化能水平为10.2 MJ/kg.     

杏鲍菇菇脚对肉兔生长性能及肉品质影响研究

研究在饲料中添加杏鲍菇废弃菇脚,并且投喂柚子皮对肉兔的生长性能及肉品质的影响。把48只30d～32d龄的新西兰肉兔随机分为3组,分别投喂0％、1％、5％烘干菇脚,同时每组又分为2组,分别投喂烘干柚子皮。结果表明添加5％杏鲍菇菇脚及投喂柚予皮均能显著降低兔粪TBARS水平,改善肠道抗氧化状况;饲喂菇脚对肉兔增重和兔肉品质没有影响,兔肉中无棉酚残留;柚子皮对增重无显著影响,但能显著降低兔肉胆固醇含量。     

Effects of different dietary energy and protein levels and sex on growth performance,carcass characteristics and meat quality of F1 Angus x Chinese Xiangxi yellow cattle

Background：The experiment evaluated the effect of nutrition levels and sex on the growth performance,carcass characteristics and meat quality of F1 Angus × Chinese Xiangxi yellow cattle.Methods：During the background period of 184 d,23 steers and 24 heifers were fed the same ration,then put into a2×2×2 factorial arrangement under two levels of- dietary energy（TON：70/80%DM）,protein（CP：11.9/14.3%DM）and sex（S：male/female） during the finishing phase of 146 d.The treatments were-（1） high energy/low protein（HELP）,（2） high energy/high protein（HEHP）,（3） low energy/low protein（LELP） and（4） low energy/high protein（LEHP）.Each treatment used 6 steers and 6 heifers,except for HELP- 5 steers and 6 heifers.Results：Growth rate and final carcass weight were unaffected by dietary energy and protein levels or by sex.Compared with the LE diet group,the HE group had significantly lower dry matter intake（DMI,6.76 vs.7.48 kg DM/d）,greater chest girth increments（46.1 vs.36.8 cm）,higher carcass fat（19.9 vs.16.3%） and intramuscular fat content（29.9 vs.22.8%DM）.The HE group also had improved yields of top and medium top grade commercial meat cuts（39.9 vs.36.5%）.The dressing percentage was higher for the HP group than the LP group（53.4 vs.54.9%）.Steers had a greater length increment（9.0 vs.8.3 cm）,but lower carcass fat content（16.8 vs.19.4%） than heifers.The meat quality traits（shear force value,drip loss,cooking loss and water holding capacity） were not affected by treatments or sex,averaging 3.14 kg,2.5,31.5 and 52.9%,respectively.The nutritive profiles（both fatty and amino acid composition） were not influenced by the energy or protein levels or by sex.Conclusions：The dietary energy and protein levels and sex significantly influenced the carcass characteristics and chemical composition of meat but not thegrowth performance,meat quality traits and nutritive profiles.     

Effects of dietary tryptophan and stocking density on the performance,meat quality,and metabolic status of broilers

Background

Highly automated cage-rearing systems are becoming increasingly popular in China. However, a high stocking density can cause oxidative stress and decrease broiler performance. The tryptophan (TRP) derivative 5-hydroxytryptophan (5-HT) has been shown to preserve membrane fluidity in birds suffering from oxidative stress. Therefore, this experiment was conducted to determine the effects of dietary TRP supplementation on performance, breast meat quality and oxidative stress in broilers reared in cages with a high or low stocking density.

Methods

Female Arbor Acres broilers (25-d-old, n = 144) were randomly allocated to 1 of 4 treatments. The birds were fed a diet based on corn, soybean meal, cottonseed meal and corn gluten meal containing either 0.18 or 0.27% TRP and were housed with stocking densities of 11 or 15.4 birds/m² in a 2 × 2 factorial experiment. Broiler performance was evaluated from d 25 to 42. Eight birds from each treatment were slaughtered on d 42 and plasma and breast muscle samples were collected to measure biochemical indices.

Results

A higher stocking density tended to be associated with reduced weight gain (P < 0.10), and significantly increased plasma glutamic-pyruvic transaminase (GPT) activity (P < 0.001). Increased dietary TRP significantly reduced the activities of lactic dehydrogenase and GPT while increasing total cholesterol in the plasma (P < 0.01), reducing drip loss of breast muscle (P < 0.10) and improving feed efficiency (P < 0.10).

Conclusions

An increase in dietary TRP, 1.5-fold higher than the standard supplementation level, can alleviate oxidative stress as well as improve welfare and feed efficiency in broilers reared in cages with a high stocking density.     

反复冻融对肉制品品质的影响

冷冻肉制品在现代肉及肉制品加工工业中起着很重要的作用,是原料肉最常用的保存方法。储存和运输时温度的波动,以及一些销售环节温度控制不当,会引起肉制品反复冷冻-解冻(反复冻融),这会引起肉制品内部的一系列生理生化反应,进而导致肉制品品质的下降。就反复冻融对肉制品品质方面的影响展开论述,以期为原料肉的合理冷冻储存提供参考。     

Effects of Dietary Lysine on Growth Performance,Serum Concentrations of Insulin-Like Growth Factor-I （IGF-I） and IGF-I mRNA Expression in Growing Rabbits

The effects of dietary lysine on production performance,serum concentrations of metabolites,growth hormone （GH）,insulin-like growth factor-I （IGF-I） and IGF-I mRNA expression in growing rabbits were examined.One hundred weaned New Zealand rabbits were allocated to individual cages and randomly offered a diet containing 5.5 （L1）,6.5 （L2）,7.5 （L3）,8.5 （L4）,or 9.5 g （L5） lysine per kg diet.The results showed that the average daily gain （ADG） of the rabbits from L3,L4 or L5 was higher than those from L1 or L2 （P 〈 0.05）.The feed gain ratio （F/G） in the rabbits from L4 or L5 was lower than those from L1 or L2 （P 〈 0.05）.Dietary lysine did not affect serum concentrations of total protein （TP）,glucose,insulin （INS）,and growth hormone （GH） （P 〉 0.05）.The quadratic effects of lysine on the serum urea nitrogen （SUN） concentration was detected （P = 0.035）.Serum IGF-I concentrations had a trend to increase quadratically with the increasing dietary lysine （P = 0.07）.A significant correlation was found between serum IGF-I concentrations （x,ng mL-1） and ADG （y,g kg-1）： y = -0.017x2 ＋ 1.984x ＋ 20.87 （R2 = 0.8982,P = 0.003）.The relative abundance of hepatic and muscular IGF-I mRNA tended to increase with increasing dietary lysine levels （P = 0.053 and 0.082,respectively）.Providing the diets mainly consisted of corn,wheat bran and peanut vine,the most appropriate dietary lysine level for growing meat rabbits from weaning to 70 d old was found to be 8.5 g kg-1,and IGF-I may be an important factor controlling growth of weaned rabbits.     

Effects of dietary supplementation with Allium mongolicum Regel extracts on growth performance,serum metabolites,immune responses,antioxidant status,and meat quality of lambs

The present study was to evaluate the effects of dried Allium mongolicum Regel (AMR) powder and its water- and fat-soluble extracts (AWE and AFE) on the growth performance, serum metabolites, immune responses, antioxidant status, and meat quality of lambs. A total of 32 male small-tailed Han lambs (5 months old; initial body weight = 34.8 ± 0.40 kg) were used in a 60-d feeding experiment after a 15-d adaptation period. The lambs were randomly divided into 4 groups (n = 8) and fed a basal diet (control, CON group), the basal diet supplemented with dried AMR powder at 10 g/d per lamb (AMR group), the basal diet supplemented with AWE at 3.4 g/d per lamb (AWE group), or the basal diet supplemented with AFE at 2.8 g/d per lamb (AFE group). Blood samples were collected on d 0, 30, and 60 in the feeding experiment (n = 8). At the end of the experiment, the lambs were sacrificed and the longissimus dorsi muscles collected. Growth performance was not significantly affected by dietary supplementation of AMR, AWE and AFE (P > 0.05). However, significantly lower albumin (P = 0.006), total protein (P = 0.006), globin (P = 0.025), and blood urea nitrogen (P = 0.024) concentrations were observed in AFE group relative to CON and AMR groups. Similarly, a significantly lower lactate dehydrogenase activity (P = 0.018) was observed in AFE group relative to AWE group, but not in other groups (P > 0.05). In addition, significantly increasing trends in glutathione peroxidase (P = 0.06) in AMR, AWE, and AFE groups were observed relative to the control group. Furthermore, significantly lower drip loss (P = 0.011) across the treatment groups and cooking loss (P = 0.048) were observed in the AMR group relative to the control group. Taken together, these results indicate that AMR and its extracts had no significant effect on lamb growth performance, antioxidant status, and immune responses, but could significantly improve meat quality without the occurrence of pathological kidney and liver lesions.     

双酶梭菌制剂对家兔生长和消化酶活性的影响

以加利福尼亚兔为试验材料,研究了双酶梭菌制剂对家兔生长及肠道消化酶活性的影响.试验用45日龄断奶加利福尼亚仔兔24只,随机分为2组,每组12只,雌雄各半.对照组饲喂基础日粮,试验组在基础日粮中按1g/kg添加双酶梭菌制剂.饲喂30d后,测定家兔的增重和消化道消化酶活性.结果表明,日粮中添加双酶梭菌制剂后,可促进家兔的生长和肠道中的消化酶活性,提高饲料的利用率.     

家兔原始卵泡卵母细胞体外发育的培养体系研究

本研究根据家兔卵巢的发育特征初步探讨了家兔卵巢卵母细胞体外发育的培养体系。采集新生或30日龄家兔卵巢在不同培养液中培养,并分析家兔卵母细胞的体外发生与成熟情况与体内正常发育的兔卵巢卵母细胞之间的差异,来筛选和优化家兔卵巢卵母细胞的体外培养体系。本试验从高糖DMEM、FSH浓度、BSA/血清等3个方面来筛选较好的培养条件,结果表明:①不添加高糖DMEM的M199培养液与添加的相比,卵巢上卵母细胞数量要多,但随着培养时间的延长,组织块上卵母细胞的形态会变得不清楚;②家兔卵巢组织在FSH浓度为50和100m IU/m l、添加血清的DMEM/F12培养液中生长较好,体外培养24d后,卵母细胞数量多,直径增加到65μm;③与添加BSA的培养液相比,添加血清的培养液中的卵巢卵母细胞生长状态较好,体外培养28d后,卵母细胞数量多,并且直径可达65μm。