Effects of varying levels of aflatoxin B1 and its ameliorant on feed intake and nutrient digestibility in crossbred lactating cows

Abstract

Twenty-five lactating cows (Karan Fries) were selected from Livestock Research Centre of ICAR-NDRI, Karnal and divided into 5 groups (T₁ to T₅) of 5 animals each based on milk yield, body weight, parity and days in milk (30-50 d). Feeding trial was conducted for 150 days and all the animals were fed as per nutrient requirements (ICAR, 2013). Group T₁ (Control group) was fed basal diet consisting of concentrate, wheat straw and green fodder. Group T₂ (Control + AFL B₁@ 20 ppb in diet above control level), T₃ (Control + AFL B₁ @ 40 ppb in diet above control level), Group T₄ (T₂ + MOS as ameliorant @ 0.20% of feed) and Group T₅ (T₃ + MOS as ameliorant @ 0.20% of feed). Seven days metabolic trial was conducted towards the end of the feeding trial to study nutrient utilization. Intake of DM, OM, CP, EE and water were found to be similar among all groups. However, DM digestibility (%) was found to be lower (P<0.05) in group T₃ (60.59±1.44) as compared to other groups, the digestibility  values being 63.69±1.59, 63.04±1.56, 63.47±0.89 and 61.65±1.31 in groups T₁, T₂, T₄ and T₅%, respectively. Also, OM digestibility (%) was lower (P<0.05) in group T₃ (63.82±1.74) as compared to groups T₁ (66.78±1.33), T₂ (66.49±1.59), T₄ (67.14±0.93) and T₅ (66.61±1.27). The nitrogen utilisation patterns in terms of N intake, faecal, urinary and milk excretion patterns were similar in all 5 groups. Therefore, supplementing the diets of lactating crossbred cows with mannan-oligiosaccharides at 0.20% of the feed appeared to mitigate the adverse effects of dietary AFB₁ in terms of enhancing DM and OM digestibility