Effect of Feeding Isoquinoline Alkaloids on Performance and Carcass Characteristics of Finishing Bulls Fed a High-Energy Diet

Feedlot diets have been associated with metabolic and digestive disorders. In-feed antibiotics, have been proposed to minimize the negative effects associated with feeding high grain diets to improve animal productivity. However, the need for reducing the use of antibiotics in food animal production systems has led to the development of alternative strategies aimed to improve animal health and performance. The objectives of this study were to assess the effects of an isoquinoline alkaloid (IQs) containing supplementation product on productive performance, apparent dry matter digestibility (ADMD), and carcass traits in feedlot yearling bulls fed a high-grain diet. Thirty-two Angus x Nelore bulls (11±3 months, 365±10 kg) were enrolled in the present study. Animals were randomly allocated to 2 treatment groups in 8 replicates: (1) no additive supplementation (CON, n=16), and (2) supplementation with 4 g/head/d of an IQs containing product (Sangrovit^® RS, Phytobiotics Futterzusatzstoffe GmbH, Eltville, Germany; SAN, n=16) top-dressed at the time of feed delivery. During the study period, all animals were fed the same high concentrate diet containing a mixture of 85% whole corn grain and 15% protein-vitamin-mineral mix twice a day as a total mixed ration. Animals received the experimental diets for a period of 119 d with an initial adaptation period of 14 d. Dry matter intake (DMI) was estimated daily by subtracting the refusals to the amount of feed delivered. Performance parameters (body weight [BW], feed efficiency [FE], average daily gain [ADG] DMI, and ADMD) were evaluated during the adaptation period, and every 21 d intervals for 5 periods. Individual carcass measurements (e.g. weight, gain, yield) were recorded at slaughter. Results indicated that DMI, BW, FE, ADG and carcass weight were not affected (P≥0.05) by treatment. However, animals in the SAN group showed improved (P<0.05) ADMD (SAN=86.96 %; CON=81.49 %), were more efficient in converting DM to carcass (SAN=8.05 kg of DM/kg carcass; CON=8.68 kg of DM/kg carcass) and had higher (P<0.05) carcass yields (SAN=56.6%; CON=55.4%) when compared to animals in the CON group. In conclusion, results from this study suggest that feeding IQs can be beneficial in favor of feed efficiency and carcass yield in finishing yearling bulls fed high grain diets.