Document Type : Research Articles
Authors
Department of Animal Science, Faculty of Animal Science and Food Technology, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran
Abstract
Introduction: The most important and widely used plant‑based protein sources in poultry nutrition are soybean meal, rapeseed meal, and canola meal. However, due to limited production and competition between humans and animals for the consumption of common protein sources, the prices of these items are increasing. Therefore, finding an alternative protein source is important (Tacon & Metian, 2008). Typically, animal‑derived protein sources contain all the essential amino acids required by poultry. Insects grow and reproduce rapidly and have a good feed conversion ratio because they are cold-blooded. They are also able to convert agricultural waste into valuable biomass with high levels of energy and protein (Collavo et al., 2005). Insects are also highly efficient protein sources, with nearly their entire biomass being edible. Mealworms are the larvae of a species of nocturnal beetle, Tenebrio molitor, from the family Tenebrionidae, found worldwide and are known as Mealworms because they are a pest of grains, flour, and stored food (Ramos et al., 2002). This larva is commercially reared worldwide and is available in live, canned, dried, and powdered forms as feed for pets, birds, and fish. The crude protein content of the dried powder of this larva is reported to be between 31 and 50 percent, crude fiber is 10 to 15 percent, ash is 3 to 5 percent, ether extract is 31 to 43 percent, and its gross energy is between 5890 and 6520 kcal/kg (Makkar et al., 2014). It has also been reported that the presence of chitin in these larvae, due to its prebiotic properties, can have beneficial effects on the consumer's immune system (Bovera et al., 2015). The nutritional composition of mealworms depends strongly on their developmental stage, diet, and environmental conditions (Siemianowaska et al., 2013). In general, considering the price of common protein sources and the possibility of less access to them in the future, the use of animal protein, including insects and their larvae, could be one of the proposed solutions (Huis et al., 2013).
Materials and Methods: An experiment was designed to investigate the effects of different dietary levels of mealworm powder on the performance and immune response of laying hens. This experiment was conducted at the Department of Animal Husbandry of Agricultural and Natural Resources University of Khuzestan. The experiment was conducted for 8 weeks (two weeks of adaptation and 6 weeks of data collection) using 120 Leghorn laying hens of the Hy‑Line W‑80 strain, in a completely randomized design with four levels of mealworm powder (0, 1, 2, and 3%) with 4 treatments, 5 replications, and 6 chickens per replication with corn-soybean based diets. Propagation, rearing, and preparation of mealworm larvae for use in diets were carried out at Sarzamin Salamat Company. Records were taken throughout the experiment. At the end of the experiment, blood and egg samples were collected for hematological, immunological, and egg quality analyses.
Results and Discussion: Chemical analysis of mealworm powder revealed 97% dry matter, 40% crude protein and 28% extract. The results showed that dietary inclusion of mealworm powder significantly improved the overall performance of laying hens compared with the control group during the experimental period. During weeks 1–2 of the experiment, performance was not affected by the experimental treatments. During weeks 3–4, feed conversion ratio decreased under the influence of mealworm consumption. During weeks 5–6, percentage production and egg mass increased under the influence of 1 and 2% mealworm consumption, and feed conversion ratio decreased with 1% mealworm consumption. Throughout the entire experimental period, chickens fed diets containing mealworm powder produced more egg mass and had better feed conversion ratios compared to the control group. The egg production efficiency index increased significantly with the inclusion of mealworm powder in the diet. Chickens fed with 1% of mealworm powder significantly reduced LDL levels compared to other groups. Alanine aminotransferase (ALT) activity increased significantly with increasing mealworm powder levels. Glucose, triglycerides, cholesterol, and aminotransferase enzyme were not affected by the experimental treatments. The highest secondary antibody titer against sheep red blood cells (SRBC) was observed in the groups fed diets containing mealworm powder.
Conclusion: Overall, the findings of this study demonstrate that dietary supplementation with 1% mealworm powder effectively improves feed conversion ratio, enhances the egg production efficiency index (EPEI), and positively influences egg quality, hematological parameters, and immune response in laying hens.
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