ISSUE FOCUS 28 FEED & ADDITIVE MAGAZINE October 2022 it was concluded that the antibacterial activity of lysozyme and the inhibition of trypsin were significantly higher. This suggests that these insects have an immunostimulant effect and promote antiparasitic activity. Or in other words: they increase the resistance of fish to certain diseases. Something similar happens with the Pacific white shrimp. This species has a high rate of early mortality when reared in captivity. But by replacing 50% of the fishmeal with insect protein, a better feed conversion can be achieved, which ultimately strengthens growth and reduces the rate of immunosuppression, probably due to the chitin content of the insects and other biofuels that counteract pathogenic infections. In the case of juvenile catfish, studies point in the same direction. In one of them, four diets were proposed with 9, 18 and 27 grams of Tenebrio molitor meal per 100 grams of feed. And it was observed that those specimens fed with at least 25% insect protein developed a significantly higher resistance to the bacterium Edwardsiella ictaluri, responsible for enteric septicemia. For decades, the aquaculture sector has used fishmeal as the main source of protein for its feed. But due to marine overexploitation, alternatives are needed to maintain or expand production. Because to get a kilo of fish meat in captivity, the industry needs up to four kilos of catches that are later transformed into feed. On the other hand, vegetable meals are much cheaper and relatively abundant, but their amino acid profile is far from that of insects. And they require a greater use of feed additives, which in large doses could cause organoleptic changes in carnivorous species. FOR THE SWINE SECTOR The swine sector has a similar need. The recent ban on zinc oxide as a feed ingredient has forced the industry to look for new alternatives to combat piglet mortality. And again, insects may be part of the solution. Since June 26th, this chemical compound cannot be used in medicated feed, because once it is released into the environment through slurry, it represents a dangerous threat. Zinc oxide does not solubilize easily, nor does it degrade, nor is it assimilated by bacterial life in the soil, which means that it can pollute groundwater in a short period of time. This implies that the environmental risks associated with its use are greater than the benefits it can bring in the short term. Farmers must now find an alternative to replace that additive, which was used to control early mortality caused by E. coli bacteria. And they must do so urgently, since the law has also drastically restricted the use of antibiotics. The key to combat those dangerous gastric infections that threaten piglets may lie in nutrition. Tenebrio molitor meal has a minimum degree of processing and has been shown to improve both the apparent and standardized digestibility of feed, favoring the use of all the ingredients that compose it. And especially, of some essential amino acids that can help the animal's growth, such as Histidine, Arginine and Cysteine. At an optimal concentration of up to 10% of the diet, this protein produces improvements in the immunological indicators IgG and IgA. And at the same time, it reduces the fecal concentration of Salmonella and E. coli. To complete the diet, synthetic amino acids and by-products such as olive pomace polyphenols and sodium butyrate can be included. It is estimated that between 10% and 15% of piglets die during the first two weeks of life. And one
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