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 per-formance,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.

New horizons for selenium in animal nutrition and functional foods

Selenium(Se),one of the indispensable nutrients for both human health and animal growth,participates in various physiological functions,such as antioxidant and immune responses and metabolism.The role of dietary Se,in its organic and inorganic forms,has been well documented in domestic animals.Furthermore,many feeding strategies for different animals have been developed to increase the Se concentration in animal products to address Se deficiency and even as a potential nutritional strategy to treat free radical-associated diseases.Nevertheless,studies on investigating the optimum addition of Se in feed,the long-term consequences of Se usage in food for animal nutrition,the mechanism of metallic Se nanoparticle(SeNP)transformation in vivo,and the nutritional effects of SeNPs on feed workers and the environment are urgently needed.Starting from the absorption and metabolism mechanism of Se,this review discusses the antioxidant role of Se in detail.Based on this characteristic,we further investigated the application of Se in animal health and described some unresolved issues and unanswered questions warranting further investigation.This review is expected to provide a theoretical reference for improving the quality of food animal meat as well as for the development of Se-based biological nutrition enhancement technology.

Heat stress inhibits proliferation, promotes growth, and induces apoptosis in cultured Lantang swine skeletal muscle satellite cells

Proliferation suppression and apoptosis are the prominent characteristics induced by heat stress（HS） in cells, whereas the effects of HS on cell growth（mass accumulation） are unknown. In this study, Lantang swine（an indigenous breed of China） skeletal muscle satellite cells（SCs） were pre-cultured at 37 °C for 24 h. The HS group was subjected to HS at 41 °C, while the control group was maintained at 37 °C. Heat shock protein 70（HSP70） expression and SC size are significantly increased（P〈0.05） by HS, but cell proliferation is suppressed（P〈0.05） and apoptosis is induced（P〈0.05）. HS led to a lower percentage of SCs in the G0/G1 phase（P〈0.05） together with a higher percentage of SCs in the S phase（P〈0.05）. However, the percentage of SCs in the G2/M phase was decreased（P〈0.05） at 48 h but then increased（P〈0.05） at 72 h with HS. In addition, the phosphorylation ratios of protein kinase b（Akt）, ribosomal protein S6 kinase（S6K）, and ribosomal protein S6 were increased（P〈0.05） by HS. Nevertheless, the phosphorylation ratios of the 4E binding protein 1 and the eukaryotic initiation factor-4E were indistinguishable（P〉0.05） from those of the control group. The phosphorylation ratio of the mammalian target of rapamycin（m TOR）（Ser^2448） increased（P〈0.05） within 48 h, and apparent differences were abrogated at 72 h（P〉0.05）. Moreover, cleaved caspase-3 expression was increased at 72 h（P〈0.05）. These findings indicate that HS induces apoptosis and disrupts cell cycle distribution to decrease the number of cells. Additionally, HS can promote SC growth via an activated Akt/m TOR/S6 K signaling pathway.

The in ovo injection of methionine improves intestinal cell proliferation and differentiation in chick embryos by activating the JAK2/STAT3 signaling pathway

The intestinal health of chick embryos is vital for their life-long growth,and exogenous nutrition intervention may provide sufficient nutrition for embryonic development.In the present study,we investigated the effect of in ovo injection of L-methionine(L-Met)on the intestinal structure and barrier function of chick embryos.There were 4 groups of treatments:the control(CON)group injected with phosphate-buffered saline(PBS)and the other 3 groups injected with 5,10,and 20 mg L-Met/egg,respectively.The injection was performed on embryonic day 9(E9),and intestinal samples were collected on the day of hatching for analysis.The results showed that,compared with the CON group,the groups administered an in ovo injection of L-Met increased relative weights of the duodenum,jejunum,and ileum(P<0.05).Hematoxylin and eosin(H&E)staining showed that the groups injected with 5,10,and 20 mg L-Met significantly increased villus height and crypt depth(P<0.05).Moreover,in ovo injection of 10 mg L-Met also increased the transepithelial electrical resistance(TEER)of the jejunum(P<0.05).Injection with 10 and 20 mg L-Met increased the expression of the tight junction proteins(ZO-1 and claudin-1)and the fluorescence signal intensity of Ki67 and villin proteins(P<0.05).Further,the protein expression of phospho-Janus kinase 2(p-JAK2)and phospho-signal transducer and activator of transcription 3(p-STAT3)was significantly increased by 10 or 20 mg L-Met injection(P<0.05).In conclusion,the injection of L-Met,especially at a dose of 10 mg,showed beneficial effects on the intestinal integrity of chick embryos due to the activation of the JAK2/STAT3 signaling pathway.Our results may provide new insights for regulating the intestinal development of embryonic chicks and the rapid growth of chicks after hatching.

Growth of embryo and gene expression of nutrient transporters in the small intestine of the domestic pigeon(Columba livia)

The objective of this study was to investigate the relationship between gene expression of nutrient（amino acid, peptide, sodium and proton） transporters in the small intestine and embryonic growth in domestic pigeons（Columba livia）. One hundred and twenty-five fertilized eggs were randomly assigned into five groups and were incubated under optimal conditions（temperature of 38.1 °C and relative humidity of 55%）. Twenty embryos/birds from each group were sacrificed by cervical dislocation on embryonic day（E） 9, 11, 13, 15 and day of hatch（DOH）. The eggs, embryos（without yolk sac）, and organs（head, brain, heart, liver, lungs, kidney, gizzard, small intestine, legs, and thorax） were dissected, cleaned, and weighed. Small intestine samples were collected for RNA isolation. The m RNA abundance of intestinal nutrient transporters was evaluated by real-time reverse transcription-polymerase chain reaction（RT-PCR）. We classified these ten organs into four types according to the changes in relative weight during embryonic development. In addition, the gene expression of nutrient transporters was differentially regulated by embryonic day. The m RNA abundances of b^0,＋AT, EAAT3, y^＋LAT2, Pep T1, LAT4, NHE2, and NHE3 increased linearly with age, whereas m RNA abundances of CAT1, CAT2, LAT1, EAAT2, SNAT1, and SNAT2 were increased to higher levels on E9 or E11 and then decreased to lower levels until DOH. The results of correlation analysis showed that the gene expressions of b^0,＋AT, EAAT3, Pep T1, LAT4, NHE2, NHE3, and y^＋LAT2 had positive correlations with body weight（0.71〈correlation coefficient（CC）〈0.82, P〈0.0001）, while CAT1, CAT2, EAAT2, SNAT1, and SNAT2 had negative correlations with body weight（-0.86〈CC〈-0.64, P〈0.0001）. The gene expressions of b^0,＋AT, EAAT3, LAT4, Pep T1, NHE2, NHE3, and y^＋LAT2 showed positive correlations with intestinal weight（0.80〈CC〈0.91, P〈0.0001）, while CAT1, CAT2, and EAAT2 showed negative correlations with intestinal weight（-0.84〈CC〈-0.67, P〈0.0001）. It was concluded that the differences between growth trajectories of organs and gene expression of nutrient transporters in small intestine were due to their functional and physiological properties, which provided a comprehensive study of amino acid and peptide transporter m RNA in the small intestine during embryonic growth of pigeons.