Melanine protein-energy additive from Hermetia illucens larvae in nutrition of calves

One of the natural sources of various biologically active substances, including melanin, are insects. In connection with the possibility of industrial breeding of some insect species for feed purposes and obtaining various products of processing their biomass, an assessment of the biological effectiveness of the substances obtained is necessary. The purpose of the present studies was to study the effectiveness of the use of the melanin protein-energy additive (MPEA) from the larva of the Hermetia illucens fly, in feeding black-and-white breed calves to enhance their safety and growth. Researches were carried out on 30 calves of black-and-white breed on the basis of experimental farm «Klenovo-Chegodaevo», Moscow. According to the principle of animal analogues, 3 groups of calves were formed, 10 animals in each. In the first period of the experiment (1-2 months old calves), the animals of the group 2 were fed individually with 5.0 ml of MPEA (6 mg melanin per head daily), and the animals of the group 3 were fed with 7.5 ml of MPEA (9 mg melanin per head daily). Starting from 3 month age, a daily dose of the additive was increased to 7.5 and 10 ml per head, respectively, in the experimental groups. The duration of the experiment was 89 days. The study of the chemical composition of MPEA showed the absence of crude fiber (chitin), with a high content of protein, fat, minerals. In the experimental additive the concentration of melanin was 1.2 mg melanin/ml. MPEA practically did not contain pathogenic microorganisms and was recognized as non-toxic. During the experiment, the calves receiving the MPEA an average daily gain and gross gain were 4.13-2.43 kg and 46.44-27.34 g (or 4.23 and 2.49 %) higher, res[ectively, than those in the control group, with 4.1 and 2.4 % decrease in feed consumption per 1 kg of live weight gain. In the calves of the experimental groups, there was a tendency for lowering total blood protein level by 3.45 and 2.71 g/l compared to the control due to reducing the fractions of albumins by 1.86 and 1.29 g/l, and globulins by 1.60 and 1.43 g/l, respectively. Also, ALT activity decreases by 4.3 IU/l (p 0.05 for group 3) and 2.38 IU/l (p 0.05 for group 2). The content of lysozyme, per cent of lysis, the blood BA level of the calves from the experimental groups turned out to be practically the same, 0.47-0.49 μg/l, 27.27-28.28 %, and 80.39-82.35 %, respectively. However, the FA index of the calves from the group 2 and group 3 was 5.94 and 6.95 % higher, respectively, compared to the control. In the calves of the group 2 and group 3, the number of lacto- and bifidobacteria in the colonic intestine increased, by 2.23×105 and 10.3×105 CFU/g for Lactobacillus, and by 0.33×108 and 1.07×108 CFU/ml for Bifidobacteria compared to the control. There was a decrease in the amount of lactose-positive coliforms by 1.196×105 and 1.11×105 CFU/g, respectively, compared to the control animals. Calculation of the feeding efficiency of the MPEA during the experiment showed a profitability of (+)381.65 and (+)180.90 rubles, or (+)4.29 and(+) 2.03 rubles per head daily, in the experimental calves when compared to the control animals. MPEA dosage was established experimentally, and, possibly, is not definitively precise, since this is the first study of MPEA biological effectiveness for calves. Further research is needed to identify the biological effect of the Hermetia illucens larvae on various species of farm animals.