Journal of Poultry Science最新文献

Poultry meat and egg production benefits from a smaller carbon footprint, as well as feed and water consumption, per unit of product, than other protein sources. Therefore, maintaining a sustainable production of poultry meat is important to meet the increasing global demand for this staple. Heat stress experienced during the summer season or in tropical/subtropical areas negatively affects the productivity and health of chickens. Crucially, its impact is predicted to grow with the acceleration of global warming. Heat stress affects the physiology, metabolism, and immune response of chickens, causing electrolyte imbalance, oxidative stress, endocrine disorders, inflammation, and immunosuppression. These changes do not occur independently, pointing to a systemic mechanism. Recently, intestinal homeostasis has been identified as an important contributor to nutrient absorption and the progression of systemic inflammation. Its mechanism of action is thought to involve neuroendocrine signaling, antioxidant response, the presence of oxidants in the diet, and microbiota composition. The present review focuses on the effect of heat stress on intestinal dysfunction in chickens and the underlying causative factors. Understanding these mechanisms will direct the design of strategies to mitigate the negative effect of heat stress, while benefiting both animal health and sustainable poultry production.

Exogenous phytases are commonly added to low-phosphorus and low-calcium diets to improve P availability and reduce P excretion by poultry. This study investigated the effect of supplementation with a novel bacterial 6-phytase on egg production, egg quality, bone mineralization, and precaecal digestibility of P in laying hens fed corn-soybean meal-based diets. A total of 576 Hy-Line brown laying hens were used in a completely randomized block design at 25-45 weeks of age (woa). The three treatments included a positive control (PC) adequate-nutrient diet with 2840 kcal metabolizable energy/kg, 0.77% digestible lysine, 3.5% Ca, and 0.30% available P (avP); a negative control (NC) diet with 0.16% points less Ca and avP; and an NC diet supplemented with a novel bacterial 6-phytase at 300 phytase units/kg diet. Hen performance and the percentage of damaged eggs were measured every 4 weeks. Body weight, precaecal digestibility of P, and bone parameters at 45 woa were also measured. The reduction in avP and Ca in the NC diet did not compromise performance or egg quality. However, it decreased (P < 0.001) body weight, tibial dry matter, tibial ash and P content, and precaecal digestibility of P. Importantly, all these parameters were significantly improved (P < 0.001) and essentially restored to the levels measured in PC diet-fed hens upon supplementation with phytase. In summary, the present study demonstrates that the new bacterial 6-phytase could effectively counteract the negative effects of P and Ca deficiencies on body weight, bone mineralization, and P availability, thereby supporting high productivity without compromising the welfare of laying hens.

Artemisia annua L. is a natural herb with a variety of bioactive substances, which can play a variety of biological functions such as anti-inflammatory, antioxidant, antibacterial and antiviral, and can be used as a potential feed additive. The purpose of this study was to investigate the effects of different doses of Artemisia annua L. water extract (AAWE) on growth performance and intestinal related indicators in broilers. A total of 200 one-day-old Arbor Acre broilers were selected and randomly divided into five treatment groups, with five replicates in each group and eight birds per replicate. The control group was fed a basal diet, whereas the other groups were fed a basal diet supplemented with 0.5, 1.0, 1.5, or 2.0 g/kg AAWE. On d 21, with the increase in AAWE dose, final body weight and feed efficiency showed a quadratic increase effect, whereas feed intake showed a linear reduction effect; however, the apparent metabolic rate of dry matter, crude protein, and ether extract increased quadratically on d 42. In addition, the activity of duodenal chymotrypsin and trypsin, and of jejunal lipase quadratically increased, whereas the intestine crypt depth linearly decreased on d 42. The number of total anaerobic bacteria increased quadratically, whereas the number of Escherichia coli decreased quadratically. The number of Lactobacillus increased linearly, whereas H₂S emission linearly decreased on d 21; moreover, NH₃ emission (24 h) quadratically decreased on d 42. In conclusion, AAWE promoted the growth performance and intestinal related indicators of broilers.

Although the nutrient requirements of geese during the growing stage are known, the dietary requirement of amino acids during the starting period remains unclear. Optimum nutrient supplementation during the starting period is crucial for improved survival rates, body-weight gain, and marketing weight in geese. Our study focused on the effect of dietary tryptophan (Trp) supplementation on the growth performance, plasma parameters, and internal-organ relative weights in 1-28-day-old Sichuan white geese. A total of 1080 1-day-old geese were divided randomly into six Trp-supplemented (0.145%, 0.190%, 0.235%, 0.280%, 0.325%, and 0.370%) groups. Average daily feed intake (ADFI), average daily gain (ADG), and duodenal relative weight were highest in the 0.190% group, brisket protein level and jejunal relative weight in the 0.235% group, and plasma total protein and albumin levels in the 0.325% group (P < 0.05). Dietary Trp supplementation did not significantly affect the relative weights of the spleen, thymus, liver, bursa of Fabricius, kidneys, and pancreas. Moreover, the 0.145% - 0.235% groups showed significantly decreased liver fat (P < 0.05). Based on the non-linear regression analysis of ADG and ADFI, the dietary Trp levels between 0.183% and 0.190% were estimated to be optimal for 1-28-day-old Sichuan white geese. In conclusion, optimal dietary Trp supplementation in 1-28-day-old Sichuan white geese resulted in increased growth performance (0.180% - 0.190%) along with improved proximal intestinal development and brisket protein deposition (0.235%). Our findings provide basic evidence and guidance for optimal levels of Trp supplementation in geese.

Abstracts: Skeletal muscles have a high demand for ATP, which is met largely through mitochondria oxidative phosphorylation. Autophagy is essential for the maintenance of skeletal muscle mass under catabolic conditions. This study investigated the effect of uncoupling mitochondrial oxidative phosphorylation on autophagy in chicken skeletal muscle. Chick myotubes were incubated with the mitochondrial uncoupler carbonyl cyanide m-chlorophenyl hydrazone (CCCP) at 25 μM for 3h. CCCP prevented the phosphorylation of p70 ribosomal S6 kinase 1 (Thr389), S6 ribosomal protein (Ser240/244), and eukaryotic translation initiation factor 4E-binding protein 1 (Thr37/46), which are the measures of the mechanistic target of rapamycin complex 1 (mTORC1) activity. CCCP significantly increased cytoplasmic and mitochondrial LC3-II content, which act as indices of index for autophagosome formation and mitophagy, respectively, but did not influence the expression of autophagy-related genes LC3B, GABARAPL1, and ATG12. Finally, surface sensing of translation method revealed that protein synthesis, a highly energy consuming process, was significantly decreased upon CCCP treatment. These results indicate that the uncoupling of mitochondrial oxidative phosphorylation stimulates autophagy and inhibits protein synthesis through mTORC1 signaling in chick myotube cultures.

The concentration of N^τ-methylhistidine in plasma provides an index of skeletal muscle protein breakdown. This study aimed to establish a quantitative method for measuring the concentrations of N^τ-methylhistidine and its isomer N^π-methylhistidine in chicken plasma, using liquid chromatography-tandem mass spectrometry with stable isotope dilution analysis. The acceptable linear ranges of detection were 1.56-50.00 μmol/L for N^τ-methylhistidine and 0.78-25.00 μmol/L for N^π-methylhistidine. The proposed method detected changes in the plasma levels of N^τ-methylhistidine and N^π-methylhistidine in response to fasting and re-feeding. These results suggest that the method developed in this study can be used for the simultaneous measurement of N^τ-methylhistidine and N^π-methylhistidine in chicken plasma.

Red junglefowl (RJF) is considered the ancestor of domestic chickens. However, the possible maternal origin, genetic diversity, and subspecies classification of the Philippine (PH) RJF remains uncertain. In this study, the complete mitochondrial DNA (mtDNA) D-loop sequence of 55 PH RJFs collected from the mountainous areas of Occidental Mindoro, Palawan, Agusan del Norte, Capiz, Leyte, Iloilo, and Guimaras were analyzed and compared with chicken reference sequences. Phylogenetic analysis revealed multiple maternal origins of the PH RJFs based on haplogroups D, E, and Y classification. This was supported by PH RJFs and RJFs from other Asian countries sharing a clade. A median-joining network also revealed the haplotype sharing of the PH RJFs and Indonesian RJF, demonstrating common maternal ancestry. High haplotype and nucleotide diversity were also observed at all sampling sites. Analysis of molecular variance indicated that the principal molecular variance existed within populations (81.23%) rather than among populations (18.77%). A population neutrality test and Bayesian skyline plot (BSP) analysis elucidated the RJF maternal effective population size expansion in the Philippines that possibly started approximately 2,800-3,000 years ago. The co-existence of Gallus gallus bankiva and Gallus gallus gallus in the Philippines was also verified. The haplotype sharing of the current RJF samples with commercial chickens suggested the need to formulate conservation programs that would protect the RJFs in the Philippines.