Does the provision of live black soldier fly and yellow mealworm larvae improve Muscovy duck welfare?

Background The provision of environmental enrichments to Muscovy ducks could reduce the expression of the aggressive behaviors.The aim of the present study was to evaluate the effects of black soldier fly(BSF)and yellow mealworm(YM)live larva provision on Muscovy duck performance,excreta corticosterone metabolites(ECM),behavior,and blood parameters.Methods A total of 1263-day-old female Muscovy ducklings were allotted to 18 pens(6 replicates/treatment,7 birds/pen)and assigned to 3 experimental treatments:a control group fed commercial feed,and two experimental treatments fed commercial feed plus the 5%(based on the expected daily feed intake,as fed basis)of BSF and YM live larvae(BSF and YM groups,respectively).A two-phase feeding program was applied:starter(from 3 to 31 days of age)and grower-finisher(from 32 to 55 days of age).The live weight,average daily gain,average daily feed intake,and feed conversion ratio were calculated.Larva consumption times were collected,and video recordings were performed during 3 periods(P)each day:the hour before(P1),during(P2),and after(P3)the larva administration.ECM were evaluated at 3,31,and 55-day-old.Finally,the total red and white blood cell counts,serum proteins,lipids,and liver and renal function serum enzymes were evaluated on 12 birds/treatment.Results The experimental treatment did not affect the growth performance of the birds(P>0.05).Larva consumption times were always similar between the two insect species,except at 14–18 days of age,were BSF larvae were consumed faster than YM larvae(P<0.001).The birds showed less walking activity during P2,and preening behavior increased in YM birds during P3.The C birds increased the attack behavior over the weeks(P<0.05).During weeks 1–3 the YM group reduced the attack frequency(P1>P3;P<0.05).Finally,the provision of live BSF and YM larvae significantly reduced the ECM at 55 days of age and the heterophil to lymphocyte ratio(P<0.05).Conclusions Live BSF and YM larva supplementation in Muscovy duck improves duck welfare,without impairing birds'growth performance.

Effect of the rearing diet on gene expression of antimicrobial peptides in Hermetia illucens(Diptera:Stratiomyidae)

Insect proteins have been proposed for human and animal food production.Safeguarding the health status of insects in mass rearing allows to obtain high-quality products and to avoid severe economic losses due to entomopathogens.Therefore,new strategies for preserving insect health must be implemented.Modulation of the insect im-mune system through the diet is one such strategy.We evaluated gene expression of two antimicrobial peptides(one defensin and one cecropin)in Hermetia illucens(L.)(Diptera:Stratiomyidae)reared on different diets.Analyses were performed on prepupae and 10-day-old larvae reared on cereal-and municipal organic waste-based diets and on only prepupae reared on a cereal-based diet supplemented with sunflower,corn,or soybean oil.The inclusion of sunflower oil at different points in the cereal-based diet was also evalu-ated.Moreover,diet-driven differences in the inhibitory activity of the hemolymph were tested against Escherichia coli DH5αand Micrococcus yunnanensis HI55 using diffusion assays in solid media.Results showed that a municipal organic waste-based diet produced a significant overexpression of antimicrobial peptides only in prepupae.Inclusion of veg-etable oils caused an upregulation of at least one peptide,except for the corn oil.Higher expression of both genes was observed when sunflower oil was added 5 days before pupa-tion.All hemolymph samples showed an inhibitory activity against bacteria colonies.Our results suggest that municipal organic waste-based diet and vegetable oil-added diet may successfully impact the immune system of H.illucens.Such alternatives may also exist forotherspeciesofeconomic interest.