Addition of Different Levels of Humic Substances Extracted from Worm Compost in Broiler Feeds.

Different sources and inclusion levels of humic substances (HS) have been tested in broiler rations as an alternative to the addition of growth promoter antibiotics (GPA) with promising results. The current study was carried out to assess the influence of HS extracted from worm compost on broiler production parameters, carcass yield, tibia characteristics, lactic acid bacteria (LAB) counts, excretion of Eimeria oocysts, and antioxidant status of breast meat. A total of 1200 broilers were used, housed in groups of 30 per pen, and assigned to five treatments: 1 = basal diet with GPA (positive control), 2 = basal diet without GPA (negative control), 3-5 = basal diet with 0.15, 0.30, and 0.45% HS, respectively. The data was subjected to a variance analysis and orthogonal contrasts. The FI decreased linearly (p < 0.05) from 1-14, 29-42, and 1-42 days as the inclusion of HS in the feed increased. The FCR had quadratic responses (p < 0.01) from 29-42 and 1-42 days concerning the HS inclusion levels. Lactic acid bacteria was higher (p ˂ 0.05) in ten-day-old chicks with 0.45% HS in the diet. The 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity antioxidant potential decreased linearly (p < 0.05) concerning increasing HS in the feed. The results indicate that HS can be used as growth promoters in broiler feeds.

Effect of the Addition of Humic Substances as Growth Promoter in Broiler Chickens Under Two Feeding Regimens.

Humic substances (HS) from different sources have been evaluated to replace or reduce the use of growth promoter antibiotics (GPA) in the feeds of broiler chickens. The objective was to evaluate the growth performance, tibia measurements, nutrient balance, meat quality, and microbiological status of broiler fed with an HS extract (EHS) under ad libitum (ADLIB) or feed restriction (REST). Individually caged broilers (n = 180, 14-35 day of age) were assigned to a factorial arrangement of three dietary treatments: (1) positive control with bacitracin methylene disalicylate (BMD) and salinomycin; (2) negative control without BMD nor salinomycin, and (3) same as negative control with 0.25% EHS, and two feeding regimens 1) ADLIB or REST for 24 h on d 1, 7, and 14. Results were subjected to ANOVA. Positive control and EHS-fed broilers showed higher carcass yield (p < 0.05) and lower oocyst excretion (p < 0.01) compared to negative control birds. Lactic acid bacteria (LAB) and Clostridium perfringens (C. perfringens) were higher in negative control and EHS-broilers compared to positive control (p < 0.01). In conclusion, higher carcass yield, lower C. perfringens and oocyst excretion were found in positive control and higher carcass yield, higher LAB and lower oocyst excretion were found in EHS-fed broilers. Broilers subjected to REST had reduced growth performance and meat quality. In conclusion, EHS could be used to increase the carcass yield and beneficial LAB in broilers.