Larve vive di insetti come arricchimento ambientale nei polli da carne: una prospettiva multidisciplinare sulla qualità della carne

Nowadays, broilers are bred for fast growth in barren environments at high stocking densities, and studies have found that they spent approximately 80% of their time resting, thus causing a wide range of welfare problems, which are commonly found in both the conventional and the organic productions. Most of the problems related to welfare arise from the high growth rate and body weight. The use of environmental enrichments in intensive farming could have a positive effect on birds by increasing animal welfare. The aim of the study is to evaluate the effects of Hermetia illucens (HI) and Tenebrio molitor (TM) live larvae in the diets of broiler chickens on meat quality: various aspects have been taken into consideration and evaluated, such the physico-chemical analysis of the raw meat, the sensory analysis, and the effects of four different cooking methods (oven (O), bain-marie (BM), plate (P), and grill (G)) on the proximate composition of the bird breasts. A total of 180 four-day old male broiler chickens (Ross 308) were randomly allotted to 18 pens. Each pen was assigned to one of the three dietary treatments (6 replicates/treatment, 10 birds/replicate) as follows: i) control diet (C): commercial feed (two feeding phases: starter (4-11 d) and grower (12-38 d)), ii) HI: C + 5% of the expected daily feed intake (DFI) HI live larvae (calculated on dry matter [DM]), and iii) TM: C + 5% of DFI TM live larvae (DM). At 39 days of age, birds were regularly slaughtered. Physico-chemical parameters of the raw meat were overall not affected by dietary treatments, positively confirming that the administration of 5% of HI or TM live larvae as environmental enrichment for broiler chicken can have a positive influence on animal welfare, without altering the final characteristics of raw meat sold to the consumers. Moreover, positive results were also displayed by the sensory analysis, since the meat from the broilers reared with the TM-enriched diet was preferred form panellists in terms of meat tenderness, juiciness and liking. As far as the cooked meat is concerned, cooking methods can affect differently the final proximate composition, especially in terms of dry matter (DM), crude protein (CP), and ash contents. In particular, the G cooking showed the highest DM and CP contents, while the P cooking produced a higher ash content when compared to the other cooking methods. These differences have been attributed to water losses during cooking, which are different depending on the cooking method and result in a concentration of nutrients. In addition, also the interactions between the diet and the cooking method were significant in terms of DM, CP, and ash contents, which resulted in higher values when meat from the C diet was cooked with the O cooking in comparison with the other groups. Such changes can be related to the different nutritional profile of the live insect larvae when compared to the commercial feed, aspect that is highlighted with the cooking procedure. However, since this represents the first study about the characterization of meat obtained by different cooking methods in poultry, the obtained results need further investigations.