Valutazione della digeribilità della farina di larve di Hermetia illucens nella dieta dell'anatra muschiata

Currently, soybean and fishmeal are the most common protein ingredients utilised in poultry diet formulations. However, their massive use is not sustainable anymore because of the increment of the prices, due to the increase of the demand for human consumption, and the pauperisation of environmental resources. Therefore, there is the need to find an alternative protein ingredient that could replace traditional sources and could be a more sustainable option. In this contest insects have been proposed protein feed material for poultry and other production animals, given their high nutritional value, the efficiency and the environmental sustainability that could characterise their massive production. The herein study is the first that tests the inclusion of increasing levels of black soldier fly (Hermetia illucens) larvae meal, at levels of 3%, 6% and 9% (HI3, HI6, HI9 respectively), in the diet of Muscovy duck (Cairina moschata domestica) and evaluate the digestibility of the diet and its effects on growth performances and histomorphological traits of the animals. For the obtainment of a statistically representative result, the experimental design comprehended six replicates for each dietary treatment and eight female ducklings for each replicate, accounting for 192 individuals. Ducks were fed isonitrogenous and isoenergetic diets divided into three phases according to the period of growth: starter, grower and finisher. The live weight and the daily feed intake of the animals were recorded throughout the trial at the end of each feeding phase to evaluate the growth performance traits through the calculation of the feed conversion ratio, the average daily feed intake, the average daily gain. At the end of each feeding phase the digestibility trial was performed including an indigestible marker in the diet and faeces were collected to determine apparent total tract digestibility coefficients of the nutrients. At the end, two animals for each replicate were slaughtered (12 individuals for treatment) and histomorphological investigations were performed on duodenum, jejunum and ileum gut segments samples. The results of statistical analyses showed that the final live weight and growth performance where not influenced by the 3%, 6% and 9% dietary inclusions of the insect meal. The apparent total tract digestibility coefficients of nutrients were only moderately affected. Indeed, no differences were reported for dry matter and organic matter apparent total tract digestibility coefficients as a result of HI meal inclusion, while for crude protein and ether extract apparent total tract digestibility coefficients a slight change was reported only in the first stage of growth, with a reduction of crude protein and an increase of ether extract apparent total tract digestibility coefficients. These increasing levels of HI inclusion did not affect the intestinal morphology of ducks. From these preliminary results, HI larvae meal, up to 9% levels, can be considered a valuable feed ingredient for ducks.