Research On Animal Production

The limited food resources in the world and in our country have increased attention to the use of alternative feeds. Insect farming is one of the proposed methods to improve food security for humans and animals. Insects grow and reproduce quickly and, because they are cold-blooded, have a good feed conversion ratio. They are also able to convert agricultural residues into biomass with suitable energy and protein value; hence there is great interest today in using insects in livestock and poultry nutrition. Soldier flies are found in tropical and subtropical regions of the world. Larvae can grow in several waste streams including: fruit and vegetable waste, human feces and animal manure, resulting in significant waste reduction and biomass of high nutritional quality for the insect. Larvae reach their maximum size after two weeks under optimal temperature and nutritional conditions. The soldier fly is not a pest and is not known to carry disease. The soldier fly is not attracted to human habitats and does not cause any nuisance. These characteristics make the soldier fly an attractive insect species for animal feeding. The aim of present study is consider the Effects of Black soldier fly (Hermetia illucens) larvae and pupae meal on meat quality and expression of some genes related to muscle development and lipid metabolism in Ross 308 broiler chickens.

Material and Methods: At the beginning of the research period, 280 male chicks of the Ross 308 strain were used, which were randomly divided into seven treatments and four replications between experimental units (ten pieces for each experimental unit). Before assigning the chickens to the experimental units, the chickens were weighed to determine their average weight, and they were assigned to the cages based on that. Experimental treatments were: control group (without additives), L0.5- a diet containing 0.5% black soldier fly Larve meal; L1- a diet containing 1.0% black soldier fly Larve meal; L1.5- a diet containing 1.5% black soldier fly Larve meal; P0.5- a diet containing 0.5% black soldier fly pupae meal; P1- a diet containing 1.0% black soldier fly pupae meal; P1.5- a diet containing 1.5% black soldier fly pupae meal. The total experimental period was 35 days. At the end of the experiment, 28 chickens (one bird per replicate) were randomly selected and slaughtered. The collected samples for mRNA expression were placed in liquid nitrogen for transport to the laboratory, then stored at -80°C. Total RNA was extracted using an RNA extraction kit and after conversion to cDNA, the relative expression of genes was measured using Real Time-PCR using gene-specific primers. Relative mRNA expression of acetyl-CoA carboxylase (ACC); fatty acid synthase (FAS), myogenic differentiation (MyoD), myogenic factor 5 (MyF5) were evaluated at breast and liver tissues. Meat tenderness was measured by a texture analyzer. A compression test with a dental probe was used to measure meat tenderness, and a cylindrical probe was used to analyze the texture composition. In the compression test, hardness and deformation parameters in hardness were measured. The final analysis of the data was performed using the GLM procedure, by SAS statistical software version 9.1. The mean comparison of the treatments was also done using Duncan's multiple range test at the error probability level of 0.05.

Results: The supplementation of dietary treatments with black soldier fly larvae and pupae meal had a significant effect on breast muscle hardness as measured by compression test.  The hardness of the samples from 0.5% and 1.0 % BSF meal (larvae and pupae) groups was double that of 1.5 BSF meal and control. Based on compression method, the 1.5% BSF meal meat exhibited the lowest hardness, followed by the control broiler samples (P < 0.05). Liver FAS expression decreased with inclusion of black soldier fly larvae and pupae meal compared to control group, conversely, breast MyoD and MyF5 expression, and liver ACC were was increased by the inclusion of black soldier fly larvae and pupae meal compared to control group (P < 0.05). The highest expression of MyoD and MyF5 genes in breast tissue was observed in chickens that used pupae at a level of 1.5%.

Conclusion: In general, the results of the present study showed that the use of black soldier fly larvae and pupae with a positive effect on the expression of genes effective in muscle growth and a decrease in the expression of key genes effective in fat production in the liver of broiler chickens, and without a negative effect on meat quality, can be investigated as a protein source to increase efficiency in broiler chicken breeding.