Heat stress is one of the most challenging environmental stressors that influence poultry production worldwide, and causes large economic losses annually (Lara & Rostagno, 2013). High ambient temperature leads to diverse deleterious impacts on physiological, immunological, and performance traits in poultry (

Background The benefits of probiotics being used in animals are well-documented via evidenced growth performance improvement and positive modulations of gut microbiota (GM). Thus, a combination of effective microorganisms (EM) has been frequently used in animal production, including broilers. However, there are only very limited reports of EM on the growth performance and the modulation in GM of partridge shank broiler chicks. Methods We attempted to evaluate the effects of a basal diet with the addition of an EM mixture on the growth performance and gut microbiome of the chicks. A total of 100 ten-day-old female partridge shank broiler chicks were randomly divided into two groups of 50 chicks each, of which, one group fed with EM supplementation in the basal diet (designated as EM-treated group), the other group just fed with a basal diet (referred as to non-EM treated group or control group). The body weight, daily feed intake, daily gain, feed conversion ratio and other growth parameters were observed and compared between EM-treated and non-EM-treated chicks, and the gut microbiota was profiled by 16S rRNA-based next generation sequencing (NGS). Results EM-treated chicks showed significantly increased performances in body weight (BW), average daily gain (ADG) and reduced feed conversion ratio (FCR). Histological observation indicated that dietary supplementation of EM significantly increased the villus heights (VH) and the ratio of villus height to crypt depth (VH/CD), while decreased the CD of jejunum, ilea, and ceca. The results of 16S rRNA-based gut microbiota analyses showed that Firmicutes accounted for the most of the relative abundance (63.24%∼92.63%), followed by Proteobacteria (0.62%∼23.94%), Bacteroidetes (0.80%∼7.85%), Actinobacteria (0.06%∼13.69%) and others in both EM-treated and non-EM-treated broiler chicks. The addition of EM could not alter the alpha diversity of gut microbiota. Compared with the non-EM-treated chicks, the abundances of bad bacteria in the phyla of Firmicutes, Euryarchaeota, and Ruminococcus were dramatically decreased in that of EM-treated chicks, while the abundances of good bacteria in the phyla of Actinobacteria and WPS-2 were significantly increased. Conclusions The supplementation of EM in feed could improve the growth performance and positively influence the morphological characteristics of the intestine, and ameliorate the community and structure of the intestinal microbiota of partridge shank broiler chicks.

The objective of this study was to investigate the effects of replacing antibiotics with Kudzu-leaf flavonoids (KLF) on the growth performances, gut epithelial development, and gastrointestinal bacteria diversities of Yellow-feathered broilers. For this purpose, total of 216 1-day-old male Yellow-feathered chickens with the similar birth weight (31.0  ±  1.0 g) were randomly divided into 3 treatments: the control treatment (CON), the kudzu-leaf flavonoids supplement treatment (KLF), and the antibiotics supplement treatment (AGP). All birds were provided with a 56 d-feeding procedure, followed by the measurement of production performances, immune organs, blood anti-oxidant parameters, intestine epithelium development, and cecal microbiota. Results showed the feed conversion ratio significantly decreased after KLF supplement compared with CON (P  <  0.05). KLF supplement partly promoted the anti-oxidant capacity on account of the increased activity of Superoxide dismutase (SOD) and the decrease content of malondialdehyde (MDA). Further, as referred to the gastrointestinal development and bacteria, ratio of villus/crypt significantly increased of ileum in KLF treatment (P  <  0.05) while a significant promition of bacterial diversity and partial representative probiotic bacteria (P  <  0.05) after KLF supplementation. Moreover, correlation analysis indicated that probitics including Bifidobacterium, Butyricimonas, Lactobacillus and Streptococcus positively correlated with production performances. In conclusion, KLF supplement may promote feed efficiency and benefit the gastrointestinal health through improving gut bacterial diversity and probiotic bacteria. The KLF might be applied as a proper antibiotic alternative.

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Rare-earth elements (REE), supplemented as feed additives, effectively improved feed conversion and production performances of monogastrics. However, very little information exists on how REE supplementation affects ruminants. In the present study, twenty-four 18-month-old Jinjiang bull cattle, with initial body weight (BW) of 374.75 ± 14.02 kg, were randomly allotted into four dietary treatments with a 15-daylong preliminary trial: a control treatment (basal diet), a 400 mg/kg REE treatment (basal diet supplemented with 400 mg REE/kg DMI), an 800 mg/kg REE treatment (basal diet supplemented with 800 mg REE/kg DMI), and a 1,200 mg/kg REE treatment (basal diet supplemented with 1,200 mg REE/kg DMI). Based on the results, the optimum supplementation scale was chosen for a 60-day-long follow-up feeding procedure. At the end of the feeding period, all bull cattle were slaughtered. Feed intake, average daily weight gain, carcass performances, meat quality, and rumen microbiota were measured. Results indicate a positive response in terms of growth performance and gastrointestinal digestibility to REE supplementation, and 400 mg/kg DMI treatment presented the most average daily feed intake (ADFI), the best average daily weight gain (ADG), and the least F/G. REE also significantly decreased the ruminal propionate content compared with control treatment. As to microbiota, despite no increases in bacterial community abundance, there was a proliferation of Bacteroidetes and Tenericutes and suppression of Actinobacteria under REE treatment. Furthermore, REE treatment significantly increased the meat protein content and decreased meat fat content. There was also an increase in the activities of the enzymes related to lipid syntheses. Fatty acid synthetase (FAS) and malate dehydrogenase (MDH) were significantly suppressed, while the activity of the lipolysis-related enzyme, lipoproteinesterase (LPL), was enhanced. In summary, REE supplementation provided an effective regulation on ruminal microbiota, facilitation of ruminal fiber digestibility, promotion of feed conversion, suppression of lipid deposition, and finally, improved the production and meat quality of beef cattle.