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Valentina Bongiorno

Phd thesis

Animal welfare and environment issues frequently influence the consumer choices in terms of meat purchase. Therefore, considering that the use of soybean – which is the main feed ingredient in poultry diet – is nowadays critical for its unsustainability, the search for alternative protein sources and rearing systems (such as free-range rearing systems, where autochthonous chicken breed represent the election choice in maintaining biodiversity and conservation) is fundamental. Insects as Black Soldier Fly (BSF, Hermetia illucens) could be an alternative to soybean, thanks to their nutritional profile, high feed conversion ratios and low greenhouse gases emission. The first trial aimed to evaluate the growth performance and meat quality parameters of Bianca di Saluzzo (BS) and Bionda Piemontese (BP) breeds, a model of slow-growing chicken, at 5, 6, 7 and 8 months of age. The results showed interesting findings. The BP displayed a higher carcass yield than the BS (P<0.01), while higher level of yellowness and lightness were observed in the females than the males, while the opposite was recorded for the redness (P<0.001), define the typical traits of such breeds. In the second trial, the effect of the BSF supplementation to a medium-growing hybrid, were observed in terms of growth and slaughter performance, health, and welfare. Interesting results have been observed on the growth, with a final body weight higher in the larvae groups (L) than the control ones (C) (P<0.05). Moreover, both the spleen and bursa of Fabricius were heavier in the L than C, indicating a positive effect on the immune system. Additionally, the gamma glutamyl-transferase was lower in the L than C (P<0.05), revealing a larvae beneficial effect on the liver function. Finally, the cholesterol tended to be lower in the L than C (P=0.090), which would be positively associated to the binding effect of chitin contained in the BSF larvae. Moving to the welfare, it has been improved as well by the larvae provision. A reduction of fear has been observed in the female L compared to the female C (P<0.001) during the avoidance distance test, in which the female L came closer to the operator than the female C. Furthermore, a higher exploration of the outdoor paddock was observed in the same animals (P<0.05). Additionally, the foraging activity of the birds increased by virtue of the live BSF larvae over time (P<0.05), as well as the standing behavior frequency, which was higher in the L than C (P<0.001) when the birds were at the end of the cycle, fundamental to maintain the birds healthy. Curiously, the heterophile lymphocyte ratio was higher in the L than C (P=0.05) and since it is a stress related parameter the competition for the larvae access could have increase the tension among birds. Another option is represented by the anticipatory behavior, due to the waiting time for the larvae provision, thus not a negative experience.

In conclusion, the promotion of alternative genotypes and local chicken breeds should be implemented in order to safeguard the biodiversity and support a more sustainable lifestyle. Moreover, the live black soldier fly larvae provision represents a useful tool which can have positive effects on the growth and slaughter performance of birds, their health and welfare, despite some parameters, such as the heterophile lymphocyte ratio should be better investigated in future research.

Research activities

The aim of my PhD project is the evaluation of Hermetia illucens live larvae provision on growth performance, animal welfare, gut health and meat quality in two slow-growing chicken strains adapted to rural farming. Inclusion of live insects larvae in poultry diet is expected to improve chicken natural behavior expression, feather condition and bird gut health. Provision of live insects larvae could also be beneficial to growth and slaughtering performance. From an economic point of view, live larvae provision is expected to be sustainable and affordable in a circular economy, including the reduction of imported soybean (for animal nutrition), agriculture waste recycling (to produce insects), poultry product with added value.


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Last update: 26/09/2023 11:39

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