Effect of humic acid substances on proteolytic activity in intestine, digestibility of crude protein and protein content in the blood of broiler chickens

Article Details: Received: 2020-10-18 | Accepted: 2020-11-27 | Available online: 2021-01-31 https://doi.org/10.15414/afz.2021.24.mi-prap.159-163 The objective of the study was to investigate the effects of dietary intake of humic substances (HS) on the proteolytic activity and the digestibility of crude protein (CP) measured as the apparent assimilable mass coefficient of CP corrected for protein catabolism (AMC N ) in the intestine as well as on the total protein and albumin content in the serum of broiler chickens (Cobb 500, n=120). Chickens (groups A, B, C / negative control) were fed with mixtures with CP (g.kg -1 DM) – Hyd1 230.20 (d 1-7), Hyd2 222.20 (d 8-28), Hyd3 209.40 (d 29-37) for 37 days. The humic substances were added into diets of experimental groups in the feed additive according to the content of humic/fulvic acids (HA/FA; g.kg -1 ) A 4.55/0.35, B 3.99/0.35, C 2.85/0.25. The body weights and feed consumption were measured once a week. The average daily weight gains and the feed conversion ratio were calculated. The dietary intake of HS had a positive effect on the increase of proteolytic activities in the intestinal apparatus and caused the significant enhancement of AMC N of birds from experimental groups on days 17, 24 and 31. However, the values of the total protein and the albumin in the serum were significantly decreased in the groups after intake of HA/FA 4.55/0.35 or 3.99/0.35 in the feed. Keywords: gut of poultry, humates, enzymatic activity, crude protein, albumin References Arif, M. et al. (2016). Impacts of dietary humic acid supplementation on growth performance, some blood metabolites and carcass traits of broiler chicks. Indian Journal of Animal Sciences , 86(9), 1073–1078. Broderick, G. A. (1987). Determination of protein degradation rates using a rumen in vitro system containing inhibitors of microbial nitrogen metabolism. British Journal of Nutrition, 58(3), 463–475. 10.1079/bjn19870114 Carvalho, L. H. M., De Koe, T. and Tavares, P. B. (1998). An improved molybdenum blue method for simultaneous determination of inorganic phosphate and arsenate. Ecotoxicology and Environmental Restoration, 1(1), 13–19. Cunniff, P. (1995). Official Methods of Analysis of Association of Official Analytical Chemists. 16th edn., Arlington, Va, USA: AOAC International. Daněk, P., Paseka, A., Smola, J., Ondracek, J., Beckova, R. and Rozkot, M. (2005). Influence of lecithin emulsifier on the utilisation of nutrients and growth of piglets after weaning. Czech Journal of Animal Science , 50,  459–465. https://doi.org/10.17221/4245-CJAS European Commission (2009). Commission Regulation (EC) No 152/2009 of 27 January 2009 laying down the methods of sampling and analysis for the official control of feed. Official Journal of European Union , 54, 1–130. Gomez-Rosales, S. and Angeles, M. D. (2015). Addition of a worm leachate as source of humic substances in the drinking water of broiler chickens. Asian-Australasian Journal of Animal Sciences , 28(2), 215–222. 10.5713/ajas.14.0321 Grieninger, G. and Granick, S. (1975). Synthesis and differentiation of plasma proteins in cultured embryonic chicken liver cells: a system for study of regulation of protein synthesis. Proceedings of the National Academy of Sciences of USA, 72(12), 5007–5011. 10.1073/pnas.72.12.5007 Gugliemo C. G. and Karasov W. H. (1993). Endogenous mass and energy losses in ruffed grouse. The Auk, 110(2), 386–390. Jamdar, S. N., Harikumar, P. (2005). Autolytic degradation of chicken intestinal proteins. Bioresource Technol. , 96(11), 1276–1284. https://doi.org/10.1016/j.biortech.2004.10.014 Koci, S. et al. (1994). The nutrient requirements and nutrient value of feeds for poultry. 1. ed.1 Nitra: Research institute of animal production, 46 pp. McMurphy, C. P., Duff, G. C., Sanders, S. R., Cuneo, S. P. and Chirase, N. K. (2011). Effects of supplementing humates on rumen fermentation in Holstein steers. South African Journal of Animal Science , 41(2), 134–140. 10.4314/sajas.v41i2.71017 Ozturk, E. et al. (2014). Performance, meat quality, meat mineral contents and caecal microbial population responses to humic substances administered in drinking water in broilers. British Poultry Science , 55(5), 668–674. 10.1080/00071668.2014.960807 Van Loon, J. C. (1980). Analytical Atomic Absorption Spectroscopy, Selected methods. New York: Academic press, 337 pp. Van Soest, P. J., Robertson, J. B. and Lewis, B. A. (1991). Methods for dietary fiber, neutral detergent fibre, and nonstarch polysaccharides in relation to animal nutrition. Journal of Dairy Science, 74(10), 3583–3597. https://doi.org/10.3168/jds.S0022-0302(91)78551-2 Windisch, W. et al. (2008). Use of phytogenic products as feed additives for swine and poultry. Journal of Animal Science , 86(14 Suppl), E140-E148. 10.2527/jas.2007-0459