Interactive effects of dietary protein concentration and aflatoxin B1 on performance, nutrient digestibility, and gut health in broiler chicks.

A 20-day trial was conducted to determine the impact of aflatoxin B1 (AFB1) and dietary protein concentration on performance, nutrient digestibility, and gut health in broiler chicks. The 6 dietary treatments were arranged in a 2 × 3 factorial with 3 crude protein (CP) concentrations (16, 22, and 26%) with or without 1.5 mg/kg AFB1 Each diet was fed to 6 replicate cages (6 chicks per cage) from zero to 20 d of age. Endogenous N and amino acid loss were estimated from birds fed a N-free diet with or without 1.5 mg/kg AFB1 A significant interaction between AFB1 and CP concentration was observed for growth performance, where reduction of BW gain, feed intake, gain:feed ratio, and breast muscle weight by AFB1 were most profound in birds fed the 16%-CP diet, and were completely eliminated when birds were fed the 26%-CP diet (AFB1 by CP interaction; P ≤ 0.023). Similarly, AFB1 reduced serum albumin, total protein, and globulin concentrations in birds fed 16 and 22% CP diets, but not in those fed the 26%-CP (AFB1 by CP interaction; P ≤ 0.071). Gut permeability was increased in birds fed AFB1-contamiated diets as measured by serum lactulose/rhamnose ratio (main effect; P = 0.04). Additionally, AFB1 tended to increase endogenous N loss (P = 0.09), and significantly reduced apparent ileal digestible energy and standardized ileal N and amino acid digestibility in birds fed the 16%-CP diet, while birds fed higher dietary CP were not affected (AFB1 by CP interaction; P ≤ 0.01). Further, AFB1 increased the translation initiation factor 4E-binding protein (4EBP1), claudin1, and multiple jejunal amino acid transporters expression (main effect; P ≤ 0.04). Results from this study indicate that a 1.5 mg AFB1/kg diet significantly impairs growth, major serum biochemistry measures, gut barrier, endogenous loss, and energy and amino acid digestibility. Aflatoxicosis can be augmented by low dietary CP, while higher dietary CP completely eliminated the impairment of performance, serum proteins, and nutrient digestibility from aflatoxicosis in zero to 20 d broiler chicks.

Prevalence and effects of mycotoxins on poultry health and performance, and recent development in mycotoxin counteracting strategies.

Extensive research over the last couple of decades has made it obvious that mycotoxins are commonly prevalent in majority of feed ingredients. A worldwide mycotoxin survey in 2013 revealed 81% of around 3,000 grain and feed samples analyzed had at least 1 mycotoxin, which was higher than the 10-year average (from 2004 to 2013) of 76% in a total of 25,944 samples. The considerable increase in the number of positive samples in 2013 may be due to the improvements in detection methods and their sensitivity. The recently developed liquid chromatography coupled to (tandem) mass spectrometry allows the inclusion of a high number of analytes and is the most selective, sensitive, and accurate of all the mycotoxin analytical methods. Mycotoxins can affect the animals either individually or additively in the presence of more than 1 mycotoxin, and may affect various organs such as gastrointestinal tract, liver, and immune system, essentially resulting in reduced productivity of the birds and mortality in extreme cases. While the use of mycotoxin binding agents has been a commonly used counteracting strategy, considering the great diversity in the chemical structures of mycotoxins, it is very obvious that there is no single method that can be used to deactivate mycotoxins in feed. Therefore, different strategies have to be combined in order to specifically target individual mycotoxins without impacting the quality of feed. Enzymatic or microbial detoxification, referred to as "biotransformation" or "biodetoxification," utilizes microorganisms or purified enzymes thereof to catabolize the entire mycotoxin or transform or cleave it to less or non-toxic compounds. However, the awareness on the prevalence of mycotoxins, available modern techniques to analyze them, the effects of mycotoxicoses, and the recent developments in the ways to safely eliminate the mycotoxins from the feed are very minimal among the producers. This symposium review paper comprehensively discusses the above mentioned aspects.