Guanidinoacetic acid supplementation in broiler chickens fed on corn-soybean diets affects performance in the finisher period and energy metabolites in breast muscle independent of diet nutrient density

(1) Guanidinoacetic acid (GAA) is the single immediate endogenous precursor of creatine (Cr). It was hypothesised that dietary GAA would have different effects on performance and energy metabolites in breast muscle depending on the nutrient density (ND) of corn-soybean-based diets.

(2) A total of 540 one-day-old male Ross 308 broilers were allocated to 9 dietary treatments with 6 replicates (10 birds each) in a 3 × 3 factorial arrangement with three levels of ND (low, 2800; medium, 2950 and high, 3100 kcal metabolizable energy (ME)/kg; and with the other nutrients being constant relative to ME) and supplemented with three levels of GAA (0, 0.6 and 1.2 g/kg) in a 42-d feeding trial.

(3) In the starter and grower periods, increasing levels of ND improved body weight (BW), average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR), with the exception of ADFI in the starter period. GAA supplementation did not affect performance characteristics. All performance indicators responded markedly to increasing ND in the finisher period, whereas the highest GAA level reduced ADFI compared to the unsupplemented control (156 vs. 162 g/d) and concomitantly FCR (1.81 vs. 1.93). No interactive effects were noted for any performance trait. The high ND diet resulted in more breast meat yield on d42, associated with higher fat content and darker colour compared to the other ND levels. The GAA supplementation did not affect carcass and breast traits. At the end of the experiment, Cr was elevated when feeding GAA at 1.2 g/kg (5455 vs. 4338 mg/kg fresh muscle).

(4) To conclude, ND had a substantial effect on performance and carcass traits, whereas any effect of GAA was limited to FCR in the finisher period and independent of diet ND level.     

Evaluation of vegetable protein in canine diets: Assessment of performance and apparent ileal amino acid digestibility using a broiler model

Recent technological advances in the human food industry with respect to meat processing have decreased the availability of animal proteins to the pet food industry which typically formulates diets with an excess of animal protein. In the long term, this is not sustainable; thus, alternative protein sources need to be investigated. This study examined three canine diets, comparing a typical animal protein‐based diet (control) with two experimental diets where the animal protein was substituted in part with vegetable protein (formulated based either on total protein or amino acid content) using a broiler model. Each diet was fed to six cages each containing two birds from day 15, 18 cages in total (36 birds). Excreta were collected from days 19 to 21. On day 23, birds were euthanized and weighed, and their ileal digesta were collected and pooled for each cage. In addition, one leg per cage was collected for evaluation of muscle mass. Results showed no significant difference in animal performance (feed intake or live weight gain) or muscle to leg proportion across the diets. Birds fed the control diet and the diet balanced for amino acid content exhibited the greatest coefficients of apparent metabolizability for nitrogen (p < .001). Birds fed the diets that contained partial replacement of animal with vegetable protein generally had greater ileal digestibility of amino acids compared to birds fed the control (animal protein) diet. Analysis of excreta showed no dietary difference in terms of dry matter content; however, birds fed the diet balanced for total protein and the diet balanced for amino acid content had significantly greater excreta nitrogen than the control (p = .038). Overall, the study suggests vegetable proteins when formulated based on amino acid content are a viable alternative to animal proteins in canine diets.     

Plantago ovata in broiler chicken nutrition: Performance,carcass criteria,intestinal morphology,immunity, and intestinal bacterial population

In this experiment, the effect of dietary Plantago ovata (PO) on performance, carcass criteria, intestinal morphology, immunity, and intestinal bacterial population of broiler chickens was evaluated. A total of 250 one‐day‐old male broiler chicks (Ross 308) were randomly assigned to five treatments containing 0, 5, 10, 15, or 20 g/kg of PO with five replicate pens and 10 birds in each replicate. Dietary PO increased body weight gain and decreased feed conversion ratio in the finisher period, improving the performance index (p < .05). Dietary treatments had no effects on carcass criteria, but breast meat percentage showed an increasing trend with incremental levels of PO in the diet (p = .069). The length of small intestine, especially jejunum section, as well as the villus height, villus width, villus area, and goblet cell numbers were significantly increased with supplemental PO (p < .05). Humoral and cellular immunity parameters, and oxidation stability of meat were improved due to use of dietary PO (p < .05). Dietary PO decreased the CFU of Escherichia coli, whereas the Lactobacilli population was increased (p = .001). Broken‐line regression revealed that dietary PO at the rate of 10 g/kg may results in the best performance in broiler chickens. This study showed that PO at the level of 10 g/kg could be considered as a beneficial feed additive in broiler diet.     

Effects of in ovo injection of chrysin,quercetin and ascorbic acid on hatchability,somatic attributes,hepatic oxidative status and early post‐hatch performance of broiler chicks

An experiment was conducted to evaluate the effects of in ovo injection of chrysin, quercetin and ascorbic acid on hatchability, somatic attributes, hepatic antioxidant status and early post‐hatch growth performance of broiler chicks. Four hundred and eighty embryonated broiler breeder eggs containing live 18‐day‐old embryos were divided into six groups of 80 eggs each. One group remained intact and served as a control group (i), whereas the other five groups were injected with the prepared injection solutions as follows: (ii) 0.05 ml distilled water; (iii) 0.05 ml distilled water containing 6 mg ascorbic acid; (iv) 0.05 ml dimethyl sulfoxide (DMSO); (v) 0.05 ml DMSO containing 4.5 mg quercetin; and (vi) 0.05 ml DMSO containing 4.5 mg chrysin. The hatchability rate, hatching weight, residual yolk sac weight, yolk sac‐free body weight, liver weight, hepatic glutathione peroxidase and total superoxide dismutase activities, as well as malondialdehyde concentrations, were not affected by the injected solutions. There were no differences between chicks hatched from the control and in ovo injected eggs in weight gain, feed intake and feed conversion ratio from 0 to 11 days of age. However, the specific contrast performed between the in ovo injected groups and intact eggs revealed that in ovo injection significantly increased hatchability rate (p = .0493). This finding also implies that our injection procedure was harmless. In conclusion, the intra‐egg injection of chrysin, quercetin or ascorbic acid at the injection rates used in this study did not have a significant effect on hatchability, somatic characteristics, early growth performance and hepatic antioxidant status of broiler chicks. However, the overall hatchability was higher in the in ovo injected eggs as compared to non‐injected ones. These findings also confirmed the harmlessness of the procedure developed for in ovo injection in this study.     

Effect of gut stress induced by oxidized wheat gluten on the growth performance,gut morphology and oxidative states of broilers

This study was to investigate the effect of oxidized wheat gluten (OG) on growth performance, gut morphology and its oxidative states of broilers. One hundred and eighty‐day‐old male broilers (10 chicks/pen) were randomly allocated into three dietary treatments: control diet (CON), diet with 8% wheat gluten (WG) and diet with 8% OG with six pens/treatment. Body weight (BW) (21 and 35 days) and average daily gain (ADG) (1–21 days and 22–35 days) decreased (p < .05) and feed conversion ratio (FCR) (1–21 days and 22–35 days) increased (p < .05) in OG treatment. Feed intake (FI) decreased (p < .05) in WG and OG treatments during 22–35 days. However, FI was not influenced by dietary treatments during 1–21 days (p > .05). The OG‐fed broilers had a lower faecal pH value (p < .05) and higher faecal moisture content (p < 05) at 14, 21, 28 and 35 days. Villus height, crypt depth and V/C value were not different (p > .05) among treatments at 21 and 35 days. Lipid peroxidation (LPO) (21 and 35 days) and malondialdehyde (MDA) (35 days) content in crop of OG treatment increased (p < .05). Oxidized glutathione (GSSG) (21 days), LPO (21 and 35 days) and MDA (21 and 35 days) content in ileum of OG treatment increased (p < .05). The reduced glutathione/oxidized glutathione (GSH/GSSG) (21 days) and (GSH) (35 days) in ileum of OG treatment decreased (p < .05). The present findings indicate that OG might be a stressor for broiler gut, which could induce oxidative stress both in crop and in ileum, and the diarrhoea as well. The growth performance of broiler was consequently depressed.     

Modulation of broilers’ caecal microflora and metabolites in response to a potential probiotic Bacillus amyloliquefaciens

Studies have found that a dietary supplement of Bacillus amyloliquefaciens improved the growth performance, increased the nutrient digestibility of hosts and modulated the intestinal microflora. A total of 360 1‐day‐old Ross broilers were randomly divided into three treatments: a control group with a basal diet, an antibiotic group with a basal diet and added colistin sulphate, and a probiotics group with a basal diet and added Bacillus amyloliquefaciens. The HiSeq high‐throughput sequencing analysis of 16S rRNA was used to investigate the differences in birds’ caecal microflora, and metabolomics was used to analyse changes in caecal metabolites. Results showed that the supplementation of Bacillus amyloliquefaciens significantly improved the BW and ADG compared with the control birds. Results of sequencing indicated that (i) 645, 670, 596 unique operational taxonomic units (OTUs) were found in birds supplemented with Bacillus amyloliquefaciens on day 7, 21 and 42, separately, (ii) due to the diversity and relative abundance of the birds’ caecal microflora, the OTUs of the caecal microflora clustered according to age and treatment, except on day 42, (iii) among the six predominate families (Ruminococcaceae, Lachnospiraceae, Enterobacteriaceae, Erysipelotrichaceae, Lactobacillaceae and Rikenellaceae), the supplementation of Bacillus amyloliquefaciens significantly increased Enterobacteriaceae on day 42, (iv) Bacillus amyloliquefaciens increased the relative abundance of Faecalibacterium and Ruminococcus on day 21, increased the Faecalibacterium and Blautia and decreased the Ruminococcus on day 42. The metabolomics of caecal metabolites showed that the dietary Bacillus amyloliquefaciens changed the caecal metabolites involved of amino acid metabolism and glyceride metabolism, and the antibiotics changed the caecal metabolites that were related to carbohydrates and amino acid metabolism on day 21.     

Effects of oral administration of different dosages of carvacrol essential oils on intestinal barrier function in broilers

Essential oils are widely used in the pharmaceutical, food and cosmetic industries, and many plant essential oils have shown that they have positive effects on broilers nutrition. This experiment was conducted to study the effects of orally administered different dosages of carvacrol essential oils on intestinal barrier function in broiler chickens. A total of eighty 28‐day‐old (1.28 ± 0.15 kg) ROSS 308 broilers were randomly allocated to four groups of 20 replicates each, with one chicken per replicate per cage, and all were fed with the same diet. Four experimental groups were orally administered 0, 200, 300 or 400 μl carvacrol essential oils at 18:00 hr every day during the 2‐week experimental period. As a result of which, the gene expression of the occludin, claudin‐1, claudin‐5, ZO‐1 and ZO‐2 in intestinal mucosa of small intestine (p < 0.05) and the goblet cell content in small intestine epithelium (p < 0.05) were significantly increased; test subjects with 300 or 400 μl carvacrol essential oils reduced the microbial counts of Salmonella spp. and Escherichia coli in the intestines (p < 0.05); Essential oils administration also significantly increased activity of the sucrase (p < 0.05) and lactase (p < 0.05) in intestinal mucosa. In conclusion, the carvacrol essential oils have positive effects on growth performance and intestinal barriers function of broilers; those effects may be related to the dosage, as administration of 300 or 400 μl was more effective than that of 200 μl.     

氟苯尼考磺酸盐在肉鸡体内的药物动力学初步研究

研究氟苯尼考磺酸盐在肉鸡体内的血药浓度及药动学特征。将12只健康三黄肉鸡,单次肌肉注射推荐治疗剂量（20mg／kg）的自制2％氟苯尼考磺酸盐。采用高效液相色谱法测定血浆药物浓度,所得数据用3P97药动软件进行分析后发现,血药浓度和时间关系符合一级吸收一室模型,选择的权重为1／C。主要药动学参数为T1／2kα：（0．28±0．04）h,T1/2Ke：（2．06±0．06）h,Cmax：（4．17±0．12）μg／mL,Tmax：（0．92±0．09）h,AUC：（16．89±0,35）μg／mL,V／F（c）：（3．52±0．13）L／kg,CL／F（s）：（1．19±0．03）L／（kg·h）,Ke：（0．34±0．01）／h,kα：（2．57±0．37）／h,A：（6．56±0．38）μg／mL。结果提示,氟苯尼考磺酸盐在肉鸡体内具有吸收迅速,分布广泛、峰浓度较高以及消除较快的动力学特征。     

金霉素和代谢物差向金霉素在肉鸡肌肉和肝脏中的残留分布

为了研究金霉素(CTC)、差向金霉素(ECTC)在肉鸡肌肉、肝脏中的残留分布情况,样品经提取液提取后过Oasis HLB SPE小柱净化,采用电喷雾正离子模式(ESI+)和多反应监测模式(MRM),用高效液相色谱-串联质谱仪检测;试验组鸡按体重以50 mg/(kg·d)剂量内服CTC,连续5 d,每天给药1次。结果表明:该方法测定肉鸡肌肉和肝脏中CTC检测限和定量限分别为5.0、10.0μg/kg。ECTC检测限和定量限分别为20.0、30.0μg/kg。CTC和ECTC在肉鸡肌肉中平均回收率分别在73.0%~95.20%和81.80%~101.60%,相对标准偏差(RSD)分别在8.85%~12.18%和2.05%~9.29%;在肉鸡肝脏中平均回收率分别在67.06%~90.80%和78.64%~106.98%,RSD分别在2.90%~8.88%和4.72%~9.48%;肉鸡肌肉和肝脏中CTC、代谢物ECTC的残留量分别在给药后第1、5 d时达到最高。肉鸡肝脏中ECTC的残留量约占总残留量的1/2。停药后CTC及其代谢物ECTC代谢缓慢,在停药第6 d时,仍能检测到CTC及其代谢物ECTC,但其残留量均低于最高残留限量(MRLs)。从保障食品安全方面考虑,建议我国将CTC和ECTC均作为金霉素的残留标示物进行监测。     

中草药和芦荟多糖对肉鸡cAMP/cGMP与免疫功能的影响

研究了内仔鸡日粮中添加中草药添加剂和芦荟多糖对环核苷酸含量与免疫功能的影响.结果表明,中草药添加荆和芦荟多糖均能显著(P＜0.05)增加内鸡体重和肝脏重量,提高血浆和肝脏的cAMP和cGMP水平,以及血浆和肝脏的cAMP/cGMP比值.中草药添加剂加芦荟多糖提高了肉仔鸡对新城疫疫苗(NDV)的抗体水平,二免后,中草药添加荆加芦荟多糖既显著提高了内仔鸡对新城疫疫苗(NDV)的抗体水平(P＜0.05),同时还增强了肉仔鸡对NDV的免疫应答.表明中草药添加剂和芦荟多糖能提高内仔鸡的体液免疫功能,日粮中添加中草药添加荆加芦荟多糖比单独使用中草药添加剂或者芦荟多糖的效果要好,充分体现了不同的化学成分形成的协同免疫效应.