Disease is the main reason for the use of antimicrobials in calf rearing, and antibiotics are commonly used to treat calves, including for unknown diseases. This leads to antimicrobial resistance, which is a challenge to the livestock industry and public health. Plant products containing high levels of phytochemicals may improve the immunity and resistance of calves against infections, thereby reducing the use of antimicrobials. This study aimed to investigate the effect of Phyllanthus emblica (Amla) fruit powder (PE) supplementation on antioxidant capacity and immune response of preweaning dairy calves. One hundred, 2-day-old, male Holstein calves were randomly assigned into five treatment groups receiving 0, 5, 10, 20, and 40 g/d PE supplementation. Antioxidant and immune indices and pro- and anti-inflammatory cytokines were analyzed from serum samples, whereas 16S rRNA was analyzed from rumen fluid and fecal samples. PE supplementation, at 5 g/d, protected calves against oxidative stress and improved antioxidant enzymes and immune and anti-inflammatory responses, showing its immunity-enhancing and protective roles against infections. However, the antioxidant capacity and immune response decreased with increasing PE levels, illustrating the adverse effects of PE supplementation at higher doses. The analysis of ruminal and fecal bacterial community abundance detected higher proportions of Firmicutes at an early age, and a higher Bacteroidetes to Firmicutes ratio at weaning, in calves supplemented with 5 g/d PE. This contributed to the development of the immune system in early life, and improved immune and anti-inflammatory responses at a later age. The overall results suggest that PE could be supplemented at 5 g/d for preweaning dairy calves to protect against oxidative stress and infections while maintaining normal gut microbial hemostasis.

Poultry rations are composed mainly of conventional cereal grains and proteins. Using non-conventional agro-industrial by-products may reduce the cost of production and thereby improve productivity. A study was conducted to evaluate the effect of dietary brewery spent grain inclusion on egg laying performance, quality parameters of bovans brown and profitability of the rations. A total of 200 pullets with similar body weight and age were randomly distributed to five treatments with four replications. The treatments were brewery spent grain (BSG) inclusion of 0, 10, 20, 30 and 40% levels for T1, T2, T3, T4 and T5, respectively. The CP and ME contents of treatment rations were 16.54-17.04% and 2871-2903 kcal/kg DM, respectively. Inclusion of the BSG in the layers ration did not affect dry matter intake, feed conversion efficiency and hen-day egg production (58.79, 57, 56.11, 55.11 and 54.13% (SEM=0.92)). Likewise, the inclusion of the BSG in the diets did not affect (albumen, yolk, shell) quality. However, feed cost decreased with the increasing level of the BSG in the rations because of its lower purchasing price. To conclude, a 40% inclusion of BSG in the diet of layers does not affect the production and the quality of the eggs and it can be economically profitable.

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