Effects of Allium mongolicum Regel supplementation on the digestibility,methane production,and antioxidant capacity of Simmental calves in northwest China

This study evaluated the effects of Allium mongolicum Regel (AM) supplementation on nitrogen (N) balance, ruminal fermentation, and antioxidant properties. Sixteen male calves were assigned randomly to four groups, and the four were added with 0 (CON), 200 mg/kg (body weight; BW) (Low AM; LA), 400 mg/kg (BW) (Middle AM; MA), or 800 mg/kg (BW) (High AM; HA) per day for each individual. AM was added on dry matter (DM) basis. The experiment lasted for 58 days. Supplementation of AM could significantly increase average daily gain, DM digestibility, acid detergent fiber digestibility, and retained N/Intake N. N digestibility and molar proportion of propionate in the MA and HA treatments were higher than that in the CON treatment (p < .05), respectively. AM supplementation significantly increased the molar concentration of total volatile fatty acid in the rumen fluid (p < .05). The ratio of acetate to propionate in the MA and HA groups was lower than that in the CON treatment (p < .05). Furthermore, AM supplementation significantly reduced methane (CH₄) (p < .05) emissions. AM supplementation significantly increased the activities of superoxide dismutase. The MA group could significantly increase the activities of glutathione peroxidase and decrease the content of malondialdehyde. Our results indicated that AM supplementation could affect the nutrient digestibility, CH₄ emission, and antioxidant capacity of Simmental calves.     

刈割次数对沙葱生长发育特性及根部贮藏物质积累的影响

以沙葱(Allium mongolicum Regel)为试材,通过研究人工播种后刈割次数对其生长发育特性及根部贮藏物质积累及产量的影响,为沙葱适宜刈割次数及适宜刈割时期的确定提供理论依据及实践指导。结果表明:随着刈割次数的增加,沙葱叶鲜重、干重及根鲜重、干重呈降低趋势(P<0.05);其地下部根长、根数、分蘖数及鳞茎直径也有不同程度的降低趋势(P<0.05);但根系中蛋白质呈增加趋势(P<0.01),可溶性糖含量呈先升高后降低的趋势,淀粉含量则先降低后逐渐升高;刈割1次的第2年抽薹率和抽薹数显著高于其他处理(P<0.01),但与对照差异不显著。沙葱当年和第2年的总产量均以年内刈割3次(处理Ⅲ)最大,分别为3192 kg·hm^-2和22266 kg·hm^-2,各处理单茬产量则随刈割次数的增加而降低。     

Effects of dietary energy on growth performance,carcass characteristics,serum biochemical index,and meat quality of female Hu lambs

This study evaluated the effects of dietary energy levels on growth performance, carcass traits, meat quality, and serum biochemical of female Hu lambs. Seventy female Hu lambs (aged 4 months) were randomly allotted to 5 dietary treatments. Lambs were fed diets with 5 levels of metabolizable energy (ME): 9.17 (E1), 9.59 (E2), 10.00 (E3), 10.41 (E4), and 10.82 MJ/kg (E5). The lambs were adapted to the experimental diets for 10 d and the experiment period lasted for 60 d. Dry matter intake and feed conversion ratio linearly (P < 0.001) increased and decreased (P < 0.001), respectively, with increasing dietary ME levels. Average daily gain (ADG) linearly (P < 0.001) increased with increasing dietary ME levels, with the highest final body weight (P = 0.041) observed in E4 group. Moreover, dietary energy level was associated with linear increases in serum total protein (TP) (P < 0.001), albumin (ALB) (P = 0.017), glucose (GLU) (P = 0.004), and low-density lipoprotein cholesterol (LDLC) (P = 0.006) concentrations, and it was associated with a quadratic decrease in serum triglyceride (TG) concentration (P = 0.002). Serum ammonia concentration, which was firstly decreased and then increased, was quadratically affected by dietary ME levels (P = 0.013). Compared with E1 group, lambs in E4 group had higher (P < 0.05) live weights, carcass weights, mesenteric fat ratio, non-carcass fat ratio, and larger loin muscle area, but lower (P < 0.05) meat colour a∗ and b∗ values, and lesser (P < 0.05) C17:0, C20:0, C18:1n-9t, C18:3n-3, and n-3 polyunsaturated fatty acids (PUFA), but greater (P < 0.05) C18:3n-6 and n-6:n-3 ratios in longissimus dorsi (LD) muscle tissue, and lesser (P < 0.05) C17:0, C18:3n-3, C22:6n-3, and n-3 PUFA in the biceps femoris (BF) muscle tissue. The results demonstrated that increasing dietary energy level improved the growth performance and affected carcass traits, serum biochemical indexes, and fatty acid profiles in different muscles of female Hu lambs. For 4-month-old female Hu lambs, the recommended fattening energy level is 10.41 MJ/kg.     

Effects of dietary Selenomethionine supplementation on growth performance,antioxidant status,plasma selenium concentration,and immune function in weaning pigs

Background

This study was designed to evaluate the efficacy of DL-selenomethionine (DL-SeMet) supplementation on growth performance, antioxidant status, plasma selenium (Se) concentration, and immune function of weaning pigs. 216 weaning pigs were randomly allocated to 6 treatments with 6 replicates each according to a complete randomized block design. Each replicate had six pigs. Diet of group one was corn-soybean basal diet without any additional Se supplement. Group 2 was supplemented with 0.3 mg/kg of Se from sodium selenite. Groups 3-6 were supplemented with 0.1, 0.3, 0.5, and 0.7 mg/kg of Se from DL-SeMet, respectively. The trial lasted for 42 days.

Results

Pigs supplemented with 0.3 and 0.7 mg/kg DL-SeMet obtained better feed gain ratio (P < 0.05). The best antioxidant ability (serum, liver, and muscle) was shown in 0.1-0.3 mg/kg DL-SeMet groups (P < 0.05). The plasma Se concentration increased as the dietary DL-SeMet level elevated. The immunity among groups was not affected.

Conclusions

DL-SeMet supplementation in the diet significantly improved the growth performance, antioxidant ability and plasma Se content of weaning pigs. DL-SeMet can replace sodium selenite in the diet of weaning pigs.     

Dietary synbiotic supplementation improves the growth performance,body antioxidant pool,serum biochemistry,meat quality,and lipid oxidative stability in broiler chickens

The present study investigated the effects of Lactobacillus acidophilus (LBA) and mannan-oligosaccharides (MOS) supplementation on the production performance, serum biochemistry, antioxidant profile, health indices, meat quality, and lipid oxidative stability of broiler chicken. A total of 252 commercial broiler chickens at 1 d old of uniform body weight were randomly allocated to 6 maize-soybean-based dietary treatments: T₁ (control diet), T₂ ( antibiotic bacitracin methylene di-salicylate [BMD] at 20 mg/kg diet), T₃ (MOS at 0.1% + LBA at 10⁶ CFU/g feed), T₄ (MOS at 0.1% + LBA at 10⁷ CFU/g feed), T₅ (MOS at 0.2% + LBA at 10⁶ CFU/g feed), and T₆ (MOS at 0.2% + LBA at 10⁷ CFU/g feed). Each treatment was assigned to 6 replicates of 7 birds. The samples for meat quality and serum biochemistry analysis were taken from 12 birds per treatment (2 birds/replicate). The results revealed better (P < 0.01) growth performance and production efficiency of birds fed either T₅ or T₆ diet compared to control or BMD supplemented diet and BMD-supplemented birds superseded the control birds. Higher (P < 0.01) serum and liver antioxidant enzyme activities, meat antioxidant capacity (2, 2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid [ABTS] and 1, 1-diphenyl-2-picrylhydrazyl [DPPH] assays], serum total protein, high-density lipoproteins (HDL) cholesterol (P < 0.05), and globulin levels (P < 0.01) were observed in birds fed either T₅ or T₆ diet compared to control or BMD supplemented birds, whereas, lower lipid oxidation (P < 0.01), cardiac risk ratio, atherogenic coefficient, atherogenic index of plasma, serum glucose, triglyceride, total cholesterol levels (P < 0.01), and serum albumin-to-globulin ratio (P < 0.05) were observed in the chickens. The pH of meat from birds fed T₄, T₅ or T₆ diet was lower (P < 0.01) compared to control and other treatments. The extract release volume (ERV), water holding capacity (WHC), and protein content of meat were higher (P < 0.05) in birds fed either T₅ or T₆ diet compared to control or BMD supplemented birds. Thus, it was concluded that the supplementation of 0.2% MOS along with LBA at 10⁶ CFU/g is optimum for better growth performance, serum biochemistry, antioxidant profile, health indices, meat quality, and lipid oxidative stability of broiler chickens.     

Effects of dietary protein/energy ratio on growth performance,carcass trait,meat quality,and plasma metabolites in pigs of different genotypes

Background

The protein/energy ratio is important for the production performance and utilization of available feed resources by animals. Increased protein consumption by mammals leads to elevated feed costs and increased nitrogen release into the environment. This study aimed to evaluate the effects of dietary protein/energy ratio on the growth performance, carcass traits, meat quality, and plasma metabolites of pigs of different genotypes.

Methods

Bama mini-pigs and Landrace pigs were randomly assigned to two dietary treatment groups (Chinese conventional diet with low protein/energy ratio or National Research Council diet with high protein/energy ratio; n = 24 per treatment) in a 2 × 2 factorial arrangement. Blood and muscle samples were collected at the end of the nursery, growing, and finishing phases.

Results

We observed significant interactions (P < 0.05) between breed and diet for total fat percentage, intramuscular fat (IMF) content, protein content in biceps femoris (BF) muscle, and plasma urea nitrogen (UN) concentration in the nursery phase; for average daily gain (ADG), average daily feed intake (ADFI), dry matter, IMF content in psoas major (PM) muscle, and plasma total protein and albumin concentrations in the growing phase; and for drip loss and plasma UN concentration in the finishing phase. Breed influenced (P < 0.05) growth performance, carcass traits, and meat quality, but not plasma metabolites. Throughout the trial, Landrace pigs showed significantly higher (P < 0.05) ADG, ADFI, dressing percentage, lean mass rate, and loin-eye area than did Bama mini-pigs, but significantly lower (P < 0.05) feed/gain ratio, fat percentage, backfat thickness, and IMF content. Dietary protein/energy ratio influenced the pH value, chemical composition of BF and PM muscles, and plasma activities of glutamic-pyruvic transaminase and gamma-glutamyl transpeptidase, and plasma concentration of UN.

Conclusions

Compared with Landrace pigs, Bama mini-pigs showed slower growth and lower carcass performance, but had better meat quality. Moreover, unlike Landrace pigs, the dietary protein/energy ratio did not affect the growth performance of Bama mini-pigs. These results suggest that, in swine production, low dietary protein/energy ratio may be useful for reducing feed costs and minimizing the adverse effects of ammonia release into the environment.

Electronic supplementary material

The online version of this article (doi:10.1186/s40104-015-0036-x) contains supplementary material, which is available to authorized users.     

沙葱黄酮对肉羊外周血淋巴细胞转化率和凋亡率的影响

本试验旨在研究饲粮中添加沙葱黄酮对肉羊外周血淋巴细胞转化率和凋亡率的影响。选用60只6月龄左右、体重(39.9±3.2)kg的小尾寒羊为试验动物,按照出生月龄和体重相近的原则,随机分为4组,每组15只羊。对照组饲喂基础饲粮,3个试验组分别在基础饲粮中添加11、22、33 mg/kg的沙葱总黄酮。预试期为15 d,正试期为60 d。正试期第60天空腹颈静脉采血,采用噻唑蓝(MTT)法测定肉羊外周血淋巴细胞转化率,采用流式细胞仪测定细胞周期、细胞凋亡率。结果表明:1)饲粮添加11、22、33 mg/kg沙葱黄酮可提高肉羊外周血淋巴细胞转化率,其中33 mg/kg组显著高于对照组(P0.05);2)与对照组相比,饲粮添加33 mg/kg沙葱黄酮能够显著提高S期和G2/M期细胞比例(P0.05);3)与对照组和11 mg/kg组相比,22和33 mg/kg组外周血淋巴细胞凋亡率显著提高(P0.05)。由此可见,饲粮中添加11~33 mg/kg沙葱黄酮可促进肉羊外周血淋巴细胞转化,并使细胞向DNA合成期转化,促进细胞分裂,对细胞凋亡有显著促进作用,以添加33 mg/kg沙葱黄酮的效果最佳。     

水果提取物对羔羊生长性能、抗氧化及肉品质的影响

本研究旨在研究日粮添加水果提取物对羔羊生长和屠宰性能、组织器官抗氧化及肉品质的影响.试验将60只体重接近的羔羊随机分为2组,每组6个重复,每个重复5只.在为期4周的饲养期间,对照组饲喂基础日粮,处理组饲喂基础日粮+150?mg/kg水果提取物.结果:粮添加150?mg/kg水果提取物对羔羊屠宰率、热胴体重、冷胴体重、内...     

Dietary supplementation with acidifiers improves the growth performance,meat quality and intestinal health of broiler chickens

This experiment was conducted to study the effects of dietary supplementation with acidifiers on the growth performance, meat quality, and intestinal health of broiler chickens. A total of 648 male Arbor Acres broiler chickens at 1 d old were randomly divided into 6 groups, and each group consisted of 6 replicates with 18 broilers per replicate. The dietary treatments were as follows: negative control (NC, the basal diet), NC + antibiotic (enramycin, 8 mg/kg, positive control [PC]), NC + phosphoric acid (PA, 0.1, 0.2, and 0.3 g/kg), and NC + lactic acid (LA, 0.3 g/kg). The feeding trial lasted for 42 d. The results showed that the feed-to-gain ratio of the NC + acidifier groups was lower than that of the NC and PC groups from 1 to 42 d (P < 0.05). Compared with the values in the NC group, the pH of breast muscle was significantly higher in the NC + PA (0.2 g/kg) and LA (0.3 g/kg) groups (P < 0.05), and the cooking loss was lower in the breast muscle of the NC + PA (0.1 g/kg) and LA (0.3 g/kg) groups (P < 0.05). In addition, the shear force of the breast muscle and thigh muscle and the pH value in the crop, gizzard and duodenum of the antibiotic and acidifier groups were significantly decreased (P < 0.05). Moreover, the trypsin, chymotrypsin, and lipase activities of the duodenum in the NC + PA (0.2 and 0.3 g/kg) groups, as well as the villus height-to-crypt depth (VH:CD) ratio of the duodenum in the NC + PA (0.1 g/kg) group was significantly greater (P < 0.05) compared with those in the NC group. Meanwhile, the number of total aerobic bacteria, Escherichia coli and Salmonella in the cecum of the NC + PA (0.1 g/kg) and LA (0.3 g/kg) groups were decreased (P < 0.05). Collectively, diet supplementation with acidifiers could improve the growth performance, meat quality, and intestinal health of broilers, in which the effects of PA (0.1 g/kg and 0.2 g/kg) are better than the other supplementations.     

Effects of different dietary sources and levels of selenium supplements on growth performance,antioxidant status and immune parameters in Ross 308 broiler chickens

1. Although different impacts of various sources of selenium (Se) on chicken performance have been largely studied, there is a lack of comparative experiments studying the effects of these sources on the immune system and antioxidant indices of broiler tissues. The aim of this study was to examine the effects of various sources and levels of dietary Se supplements on performance, antioxidant status and immune parameters in Ross 308 broiler chickens.

2. A total of 1200 1-d-old male broilers (Ross × Ross 308) were divided into 8 treatments with 6 replicate pens and 25 birds per pen. This experiment was conducted as a completely randomised design with a 4 × 2 factorial arrangement. Main factors included Se sources as sodium selenite (SS), Se-enriched yeast (SY), DL-selenomethionine (SM) and nano-selenium (NS) and levels at 0.1 or 0.4 mg/kg Se.

3. Dietary supplementation of organic Se sources significantly improved average daily gain (ADG), gain: feed ratio and European production efficiency factor (P < 0.05) compared to birds fed on diets supplemented with inorganic source. In addition, ADG was increased in response to increased level of supplemental Se. Based on contrast comparison, there were significant differences in these parameters between organic versus inorganic sources of Se. However, there was no difference between contrast comparisons of NS versus SM and SY.

4. Total anti-sheep red blood cell (SRBC) and Immunoglobulin G (IgG) titres and hypersensitivity were enhanced by increasing supplemental concentration of Se and using organic sources of Se rather than SS (P < 0.05).

5. Oxidation resistance assessment of tissues demonstrated that supplementation of organic sources of Se and increase in supplemental concentration of Se ameliorated glutathione peroxidase activity, total antioxidant capacity and malondialdehyde formation (P < 0.05). Mostly, there were significant differences between organic versus inorganic sources of Se in oxidation resistance.

6. Overall, dietary supplementation of 0.4 mg/kg Se from an organic source resulted in better production performance and immune system response. Moreover, minimum formation of malondialdehyde in broiler tissue was observed in birds fed on diets supplemented with SM at 0.4 mg/kg.

7. It can be concluded that SM is more effective than other sources of Se in reducing lipid oxidation.     

Effects of supplemental humic substances on growth performance, blood characteristics and meat quality in finishing pigs

A total of forty-eight finishing pigs were used to determine the effects of humic substances (HS) on growth performance, blood characteristics, and meat quality. The finishing pigs were assigned randomly by weight to three treatments. The dietary treatments included: 1) Control (CON; basal diet), 2) HS1 (basal diet + 5% humic substances) and 3) HS2 (basal diet + 10% humic substances). Results of the whole experimental period showed that addition of 10% HS to the diet, significantly increased average daily gain (ADG) and gain/feed (G:F) (P < 0.05). At the end of the experiment, the relative lymphocyte counts (% of total white blood cells) of pigs fed HS2 diet were higher (P < 0.05) than that of pigs fed CON diet. The Minolta color parameter a of pigs fed HS2 was similar to that of pigs fed HS1, however, it was higher (P < 0.05) than that of pigs fed CON diet. The inclusion of either 5% or 10% HS significantly decreased backfat thickness (P < 0.05). The marbling score was increased significantly (P < 0.05) when diets were supplemented with HS at a level of 10%. The results of this study suggest that HS might be utilized as a feed additive in the diet. It could improve growth performance, relative lymphocyte counts and meat quality.     

日粮添加海藻对肉牛生长性能和肉品质的影响

文章旨在评估海藻在肉牛上的应用,研究其对肉牛生长性能、血清生化和肉品质的影响.试验选择平均初始体重为(600.09±1.73)kg的荷斯坦肉牛16头,随机分为2组,每组4个重复,每个重复2头.对照组饲喂以玉米和青贮玉米为主的日粮,处理组饲喂与对照组营养水平相近的日粮,但日粮中添加15 g/kg海藻粉.试验共进行20周....     

辽宁绒山羊羔羊肉用性能和羊肉品质研究

本研究选择24只辽宁绒山羊羔羊,年龄90±3.5日龄,体重15±0.62 kg,公母各半。试验动物分成3组,1组为高能低蛋白组,饲喂1号日粮;2组为高能高蛋白组,饲喂2号日粮;3组为对照组,饲喂3号日粮。连续试验5个月,每月测量体重1次、屠宰1次,研究体增重、屠宰性能和肉品质指标。结果表明,试验1组和2组日增重均高于对照组,其最高峰分别在第4月龄和第5月龄出现,而对照组则在第3月龄出现。各组育肥后羊绒细度均无显著变化。试验1、2组屠宰率、净肉率、眼肌面积均高于对照组,其中2组与对照组差异显著（P＜0.05）。试验1组和2组肾周脂肪重均高于对照组,其肾周脂肪占胴体重比例高于对照组。试验1、2组GR值高于对照组,差异不显著（P＞0.05）。试验1、2组的嫩度值高于对照组;各组的肉色、失水率和熟肉率均差异不显著（P＞0.05）;对照组失水率低于试验1、2组;对照组熟肉率低于试验1、2组,但差异不显著（P＞0.05）。     

Effects of dietary supplementation with carnosine on meat quality and antioxidant capacity in broiler chickens

1. This study aimed to investigate the effects of carnosine supplementation on meat quality, antioxidant capacity and lipid peroxidation status in broiler chickens.

2. A total of 256 1-d-old male Arbor Acres broilers were randomly assigned to 4 treatments consisting of 8 replicates of 8 chickens each. The birds were supplied with 4 different diets: a basal diet or a basal diet supplemented with 100, 200 or 400 mg/kg carnosine, respectively. The whole experiment lasted 42 d.

3. The results showed that dietary supplementation with carnosine linearly increased the values of pH_45 min and redness and reduced drip loss of breast meat. Dietary carnosine increased the activity of antioxidant enzymes in liver, serum and breast meat and decreased the contents of lipid peroxides at 21 and 42 d of age.

4. These findings indicated that dietary supplementation with carnosine was beneficial to enhance meat quality, antioxidant capacity and decrease lipid peroxidation status of breast meat.     

牛至油对育肥猪生长性能和肉品质的影响

文章旨在研究不同浓度的牛至油对肥育猪生长性能和肉质特性的影响。试验选择32头阉割公猪和32头后备母猪随机分成4个组,对照组饲喂基础日粮,试验组分别在基础日粮中添加0.2、0.4和0.8mg/kg牛至油,试验共开展5周。试验结束后禁食12h,称重后屠宰。经过一夜的冷却,从屠体上取50cm的腰肌(每组8头,4头公猪、4头母猪)。日粮中添加牛至精油对生长猪末重、日增重、屠宰率均无显著差异(P>0.05),同时各组最长肌嫩度、屠宰后45min和24h后的pH、肉色及感官特性也无显著差异(P>0.05)。此外,脂质氧化试验结果显示,日粮添加牛至油对肌肉无明显的抗氧化作用(P>0.05)。综上所述,由于胴体和肉质属性均无显著变化,说明本试验中日粮添加不同水平牛至油对猪的肉质参数没有影响。     

Effects of dietary supplementation of Lycium barbarum polysaccharides on growth performance,immune status,antioxidant capacity and selected microbial populations of weaned piglets

Lycium barbarum polysaccharides (LBPs) are a complex mixture of highly branched and partially characterised polysaccharides and proteoglycans extracted from the goji berry. This mixture has great potential as a novel feed supplement for pigs. Two trials were conducted to evaluate the effects of supplementation with LBPs on the growth performance, immune status, antioxidant capacity and selected intestinal microbial populations in weaned piglets. In trial 1, a total of 400 weaned piglets [(Yorkshire × Landrace) × Duroc] with an average body weight (BW) of 6.34 ± 0.16 kg (21 days of age) were divided into five groups and fed a basal diet (control group) or a basal diet containing 1,000, 2,000, 4,000 or 6,000 mg/kg LBPs (supplemented at the expense of corn). Supplementation with 4,000 or 6,000 mg/kg LBPs for 2 weeks significantly increased the average daily gain (ADG) and average daily feed intake (ADFI) of the pigs compared with the control group (p < .05). In trial 2, thirty-two 21-days-old weaned piglets (BW: 6.33 ± 0.11 kg) were allotted to a control group (fed with a basal diet) or an experimental group (basal diet containing 4,000 mg/kg LBPs). The experiment lasted for 14 days. Pigs fed LBP diets exhibited an increased ADG and ADFI, and a decreased diarrhoeal incidence compared with those fed the basal diets (p < .05). Supplementation with LBPs increased the serum IgG and IgM levels (p < .05). Dietary LBPs effectively promoted antioxidant defence properties through enhancing the activities of serum, liver superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px), in addition to decreasing the malondialdehyde (MDA) content (p < .05). The addition of LBPs increased the amounts of Bacteroidetes in the ileum and caecum and the caecal contents of Lactobacillus spp. and Bifidobacterium spp. (p < .05), while decreased the populations of Escherichia coli and Firmicutes in the ileum and caecum (p < .05) compared with the control group. Our results suggest that dietary supplementation with LBPs can enhance growth performance, immune status and antioxidant capacity, and improve the intestinal microbial populations of weaned piglets.     

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.     

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 fermented garlic powder supplementation on growth performance, blood profiles and breast meat quality in broilers

The aim of this study was to investigate the effects of dietary supplementation with fermented garlic powder (FGP) on growth performance, blood profiles and breast meat quality in broilers. A total of 500 broilers were randomly allotted to 4 treatments with 5 replications per treatment and 25 chicks per pen. The experiment lasted for 5 weeks and dietary treatments were as follows: 1) CON (basal diet); 2) FGP1 (basal diet + 1 g/kg fermented garlic powder); 3) FGP2 (basal diet + 2 g/kg fermented garlic powder); 4) FGP4 (basal diet + 4 g/kg fermented garlic powder). No effects were observed (P > 0.05) in body weight gain (BWG), feed intake (FI) or feed conversion ratio (FCR) throughout the whole experiment. The white blood cell (WBC) counts, lymphocyte and immunoglobulin G (IgG) was increased (P < 0.05) in response to FGP treatments. Broilers had lower (P < 0.05) total cholesterol, triglyceride, low-density lipoprotein (LDL) cholesterol and cortisol concentrations in blood when they were provided with FGP2 and FGP4 diets. Compared with CON, FGP2 and FGP4 treatments decreased (P < 0.05) TBARS and pH in breast meat. In conclusion, FGP administration had no effect on growth performance but improved immunity and meat quality as well as decreased cholesterol and cortisol in blood.