Comparison of gamithromycin residue depletion in yellow-feather and white-feather broilers after one single subcutaneous injection

This study aimed to compare the residue depletion of gamithromycin in yellow-feather and white-feather broilers, using Sanhuang and Arbor Acres chickens as typical examples, respectively. Each breed (54 chickens) received a single subcutaneous dose of gamithromycin at 7.5 mg/kg bodyweight (BW). Tissues, including muscle, skin + fat, liver, kidney, and injection site, were collected at 6 h, 3, 5, 7, 10, 14, 21, 28, and 35 d postdrug administration. Gamithromycin concentrations in these tissues were determined using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The kinetics of gamithromycin were analyzed in different tissues using a noncompartmental method in the Phoenix software. Differences were observed in gamithromycin concentrations and kinetic characteristics in both breeds of chickens, with higher residue concentrations and longer residue times found in yellow-feathered broilers. In Sanhuang broilers, the elimination rates of gamithromycin followed this order: injection site > muscle > liver > kidney > skin + fat. The corresponding elimination half-lives (t1/2λzs) in these samples were 1.22, 1.30, 1.71, 2.04, and 2.52 d, respectively. In contrast, in Arbor Acres broilers, a different order was noted: muscle > injection site > kidney > liver > skin + fat, with corresponding t1/2λzs of 1, 1.23, 1.88, 1.93, and 2.21 d, respectively. These differences may be related to variations in pigments in various tissues of chickens of the 2 breeds. However, further investigations are warranted to discern the underlying reasons.

Investigation of potential genetic factors for growth traits in yellow-feather broilers using weighted single-step genome-wide association study

Yellow-feather broilers take a large portion of poultry industry in China due to its meat characteristics. Improving the growth traits of yellow-feathered broilers will have great significance for the Chinese poultry market. The current study was designed to investigate the potential genetic factors using the weighted single-step genome-wide association study (wssGWAS) method, which takes consideration of more factors including pedigree, sex, environment and has more accuracy than traditional GWAS. The yellow-feather dwarf chickens from Wens Nanfang Poultry Breeding Co. Ltd. were revolved to recode 9 growth traits: Average daily gain (ADG), body weight (BW) at 45 d, 49 d, 56 d, 63 d, 70 d, 77 d, 84 d, 91 d for analysis. For the results, the region 4.63 to 5.03 Mb on chromosome 15, which was the QTL overlapped in BW45, BW49, BW56, BW63, BW84, might be the crucial genetic region for growth traits. Seven GO terms and 3 KEGG pathways, GO:0005200, GO:0005882, GO:0045111, GO:0099513, GO:0099081, GO:0099512, GO:0099080, KEGG:gga04020, KEGG:gga04540, KEGG:gga04210, were detected to relevant with growth traits. The genes enriched in these biological processes (NRAS, TUBB1, ADORA2B, NTRK3, NGF, TNNC2, F-KER, LOC429492, LOC431325, LOC431324, LOC396480) might have the function in growth of yellow-feather broilers.

Lactobacillus plantarum GX17 benefits growth performance and improves functions of intestinal barrier/intestinal flora among yellow-feathered broilers

Lactobacillus plantarum has recently been found to be a natural source feed additive bacteria with great advantages in food safety and animal welfare. Discovering novel strains with commercial application potentiation could benefit the local poultry industry, and in particular support Chinese farmers. In this study, we tested a recently isolated novel strain of Lactobacillus plantarum GX17 as a feed additive on the growth performance and intestinal barrier functions of 1-day-old Chinese yellow-feather chicks. As good as other commercial probiotics, feeding with Lactobacillus plantarum GX17 showed significant improvements in humoral immune responses and enhanced the immune effect after vaccination for either the Newcastle disease vaccine or the avian influenza vaccine. This study also found that feeding with Lactobacillus plantarum GX17 improved the feed-to-weight ratio and caused a significant increase of the villus length to crypt depth ratio. Furthermore, Lactobacillus plantarum GX17 significantly up-regulated the mRNA expression of CLDN, MUC2, and TLR2, all of which are jejunum-associated barrier genes, indicating an improvement of the intestinal barrier functions by enhancing the tight junction between epithelia cells. These results are comparable to the effects of feeding the commercial complex probiotics that improve the expression levels of CLDN, ocludin, MUC2, TLR2, and TLR4. In terms of maintaining intestinal health, commercial complex probiotics increased the relative abundance of Parabacteroides and Romboutsia, while Lactobacillus plantarum GX17 increased the relative abundance of Pseudoflavonifractor. Our data suggest that Lactobacillus plantarum GX17 could enhance the intestinal absorption of nutrients and therefore improve the growth performance of Chinese yellow-feather chicks. In conclusion, compared with the commercial complex probiotics, Lactobacillus plantarum GX17 has more positive effects on the growth performance and intestinal barrier function of yellow-feather chickens, and can be used as a feed additive.

Chitosan oligosaccharide as an effective feed additive to maintain growth performance, meat quality, muscle glycolytic metabolism, and oxidative status in yellow-feather broilers under heat stress

This study investigated the effects of dietary chitosan oligosaccharides (COS) supplementation on growth performance; corticosterone, growth hormone, and insulin-like growth factor-1 concentration; relative organ weight; liver function; meat quality; muscle glycolytic metabolism; and oxidative status in yellow-feather broilers under heat stress. A total of 108 35-day-old Chinese yellow-feather broilers (BW, 470.31 ± 13.15 g) was randomly allocated to 3 dietary treatments as follow: control group, basal diet and raised under normal temperature (24°C); HS group, basal diet and raised under cycle heat stress (34°C from 10:00 to 18:00 and 24°C for the rest time); and HSC group, basal diet with 200 mg/kg COS supplementation and raised under cycle heat stress. Each treatment had 6 replication pens and 6 broilers per pen. Results indicated that heat stress decreased ADG, ADFI, gain:feed ratio, the relative weight of thymus, bursa of Fabricius, pancreas, proventriculus, gizzard, and liver, growth hormone concentration, pH_24h, muscle glycogen content, muscle superoxide dismutase and glutathione peroxidase activity, as well as increased corticosterone, alanine aminotransferase and aspartate aminotransferase level, cooking loss, muscle lactate and malondialdehyde content. Compared with the HS group, broilers in the HSC group had higher ADG, the relative weight of thymus, bursa of Fabricius, and liver, growth hormone concentration, pH_24h, muscle glycogen content, muscle superoxide dismutase and glutathione peroxidase activity, and lower serum corticosterone, alanine aminotransferase and aspartate aminotransferase level, cooking loss, and muscle lactate and malondialdehyde content. In conclusion, the results suggested that COS could be used as an effective feed additive to maintain growth performance, liver function, meat quality, muscle glycolytic metabolism, and oxidative status of yellow-feather broilers under heat stress. The improved meat quality is possibly through reducing muscle glycolysis metabolism and improving muscle oxidative status by dietary COS supplementation in broilers under heat stress.

Effects of dietary N-carbamylglutamate supplementation on growth performance, tissue development and blood parameters of yellow-feather broilers

The effects of N-carbamylglutamate (NCG) on the growth performance, tissue development, and blood parameters of broilers are unknown. In this study, 2 linked experiments were conducted to investigate the effects of 4 graded dietary levels and 3 dietary stages of NCG in a Chinese indigenous yellow-feather broiler breed during 2 growth phases: 1 to 18 d and 19 to 36 d. The dietary levels of NCG were 0.05%, 0.10%, 0.15%, and 0.20%, and dietary stages were designed to add NCG during the starter stage or grower stage or throughout the experimental period. At the age of 18 d, graded doses of NCG from 0.05 to 0.20% in the diet produced quadratic (P < 0.05) positive responses in body weight, width of intermuscular fat cingulum, liver weight, serum blood urea nitrogen, and serum low-density lipoprotein as well as linear (P < 0.05) positive responses in albumin serum concentration. The average feed per gain and mortality were unaffected by dietary NCG levels. Among 3 dietary treatments, only NCG dietary treatments throughout the experimental period improved the body weight and daily weight gain linearly (P < 0.05). The daily weight gain under the 3 dietary treatments used indicated that the most fitting dose is 0.1% NCG among the 4 dietary levels of NCG (P < 0.05). At this dose, muscle weight increased, whereas subcutaneous adipose as well as the serum contents of uric acid, triglyceride, and albumin decreased. Considering the growth performance and tissue development under the conditions used in this study, the best-fit model for NCG requirements of Chinese yellow-feather broilers was estimated from regression analysis to be 0.09 to 0.12% dietary NCG treatments during the grower stage. The modified blood parameters indicated that NCG dietary effects on broiler growth may be accompanied by modified homeostasis of arginine metabolism, lipid deposition, protein synthesis, and immune response.