Heat stress is one of the most common environmental stressors for poultry industry, and has negative influences on animal physiology, health, and productivity, with broilers particularly susceptible.
The experts, writing in the Journal of Thermal Biology, saw that dietary inclusion of S. platensis and SeNPs reduced the microbial load in broilers' diets as well.
The researchers said their study was conducted to assess the impact of dietary incorporation of Spirulina platensis and SeNPs individually or in combinations on growth performance, antioxidant status, humoral immune response, and microbial populations in diet and ileum of heat-stressed broilers.
Diets
Some 450 Ross-308 one-day chicks were fed one of nine diets with five replicate cages in two phases for 35 days.
The experimental diets were a control basal diet without supplementation or with 0.1 mg SeNPs, 0.2 mg SeNPs, 5g Spirulina, 10g Spirulina, 0.1 mg SeNPs plus 5g Spirulina, 0.1 mg SeNPs plus 10g Spirulina, 0.2 mg SeNPs plus 5 g Spirulina, and 0.2 mg SeNPs plus 10 g Spirulina per kg diet.
Findings
Dietary supplementation with Spirulina and SeNPs significantly increased body weight gain and European production efficiency factor (EPEF), which is an equation based on average daily weight gain, mortality and feed conversion, reported the authors.
The antioxidant enzymes, serum glutathione peroxidase (GPx) and superoxide dismutase (SOD), were significantly increased with dietary spirulina and SeNPs supplementation, while thiobarbituric acid reactive substances (TBARS), a by-product of lipid oxidative damage, decreased, the researchers found.
Circulating immunoglobulin IgM, IgA and IgG were increased in treated birds compared to the control ones, while the antibody titers to infectious bursal disease (IBD), Avian influenza viruses (AIV), and Newcastle disease virus (NDV) were not significantly altered, they said.
The results showed that SeNPs and Spirulina exhibited dose-dependent antimicrobial activities against ileal counts of total bacterial, total molds and yeast, coliform, E. coli, Salmonella spp. and Enterococcus spp. However, ileal populations of Lactic acid bacteria were increased with dietary spirulina and SeNPs in a dose-dependent manner, observed the team.
“These results indicate that Spirulina and SeNPs can be potentially used as growth promoters and antioxidant, immunostimulant, and antimicrobial agents in heat-stressed broilers,” concluded the authors.
