Impact of buffered sodium butyrate as a partial or total dietary alternative to lincomycin on performance, IGF-1 and TLR4 genes expression, serum indices, intestinal histomorphometry, Clostridia, and litter hygiene of broiler chickens

BACKGROUND

Sodium butyrate (SB) is a short-chain fatty acid and a safe antibiotic alternative. During 35 days, this study compared the impact of coated SB (Butirex C4) and lincomycin (Lincomix) on broiler growth, gut health, and litter hygiene in 1200 one-day-old Ross-308 broiler chicks that were randomly assigned into 5-dietary groups with 5-replications each. Groups divided as follows: T1: Basal diet (control), T2: Basal diet with buffered SB (1 kg/ton starter feed, 0.5 kg/ton grower-finisher feeds), T3: Basal diet with 100 g/ton lincomycin, T4: Basal diet with buffered SB (0.5 kg/ton starter feed, 0.25 kg/ton grower-finisher feeds) + 50 g/ton lincomycin, and T5: Basal diet with buffered SB (1 kg/ton starter feed, 0.5 kg/ton grower-finisher feeds) + 50 g/ton lincomycin. Birds were housed in a semi-closed deep litter house, where feed and water were available ad libitum. Results were statistically analyzed using ANOVA and Tukey's post hoc tests.

RESULTS

Combined dietary supplementation with SB and lincomycin (T4 and T5) significantly enhanced body weights, weight gains, feed conversion ratio, and profitability index. Also, carcasses in T4 and T5 exhibited the highest dressing, breast, thigh, and liver yields. T5 revealed the best blood biochemical indices, while T3 showed significantly elevated liver and kidney function indices. T4 and T5 exhibited the highest expression levels of IGF-1 and TLR4 genes, the greatest villi length of the intestinal mucosa, and the lowest levels of litter moisture and nitrogen. Clostridia perfringens type A alpha-toxin gene was confirmed in birds' caeca, with the lowest clostridial counts defined in T4.

CONCLUSIONS

Replacing half the dose of lincomycin (50 g/ton) with 0.5 or 1 kg/ton coated SB as a dietary supplement mixture showed the most efficient privileges concerning birds' performance and health.

Temporal variations in litterfall biomass input and nutrient return under long-term prescribed burning in a wet sclerophyll forest, Queensland, Australia

Litterfall helps maintaining nutrient return in forest ecosystems. However, the influence of long-term prescribed burning on the dynamics of litterfall biomass and carbon (C) and nitrogen (N) cycling is poorly understood. A 39-year old prescribed burning field trial in a wet sclerophyll forest, southeast Queensland, Australia, was used to investigate the interactive effects of prescribed fire regimes and temporal variation on the quantity and quality of litterfall and C and N return. Treatments included no burning (NB) since 1969, 2 yearly burning (2yrB; burned 19 times) and 4 yearly burning (4yrB; burned 9 times) since 1972. Litterfall was collected monthly on 32 occasions between 2011 and 2013. Significant temporal variation was observed in monthly and annual litterfall biomass. Both burning treatments had lower monthly inputs of total litterfall and leaf litter, mean annual cumulative litter biomass, litter C concentrations and C return via leaf litter, compared with the NB treatment. Most significant reductions in litter N concentrations and N return via litter were associated with 2yrB treatment. The 4yrB and the NB treatments did not differ significantly in terms of twig biomass, litterfall C:N ratios and N return via leaf litter. Despite both long-term prescribed burning treatments negatively impacting C return to the soil by reducing the quantity and quality of litter inputs, previous studies at the site suggest no difference in 0-10 cm soil organic carbon levels between the 4yrB treatment and the unburnt treatment. Hence a longer period of prescribed burning at the 4yrB frequency is likely required before lower C return translates to differences in ecosystem productivity in this wet sclerophyll forest ecosystem. The 2yrB can potentially alter forest C and N cycling and net primary productivity, but these alterations are unlikely to be detected through short-term studies.