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

SIMPLE SUMMARY: In recent years, humic substances (HS) have been tested as growth promoters and health enhancers in poultry with promising results. The main available sources of HS are obtained from leonardite mines; however, HS can also be extracted from organic matter that has undergone a humification process such as compost and worm compost prepared with animal manure. The present study was designed to evaluate the inclusion of different levels of HS extracted from worm compost in the feeds of broilers raised in floor pens from 1 to 42 days of age. The main benefits found in broilers fed HS were the lower feed conversion ratio and lower mortality from 1–42 days, and increased lactic acid bacteria counts in the jejunum of ten-day-old broilers compared to broilers fed diets containing an antibiotic growth promoter and an anticoccidial product. The results indicate that HS extracted from worm compost have a similar effect to HS from leonardite when added to broiler feeds. ABSTRACT: 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.