Evaluation of the suitability of a partially defatted black soldier fly (Hermetia illucens L.) larvae meal as ingredient for rainbow trout (Oncorhynchus mykiss Walbaum) diets.

BACKGROUND: Two trials were performed to evaluate a partially defatted Hermetia illucens (HI) larvae meal as potential feed ingredient in rainbow trout (Oncorhynchus mykiss Walbaum) diets. In the first trial, 360 trout (178.9 ± 9.8 g of mean initial body weight) were randomly divided into three experimental groups (4 tanks/treatment, 30 fish/tank). The fish were fed for 78 days with isonitrogenous, isolipidic and isoenergetic diets containing increasing levels of HI, on as fed basis: 0% (HI0, control diet), 25% (HI25) and 50% (HI50) of fish meal substitution, corresponding to dietary inclusion levels of 0, 20% and 40%. In the second trial, 36 trout (4 tanks/treatment, 3 fish/tank) were used to evaluate the in vivo apparent digestibility coefficients (ADC) of the same diets used in the first trial. RESULTS: Survival, growth performance, condition factor, somatic indexes, and dorsal fillet physical quality parameters were not affected by diet. The highest dietary inclusion of HI larvae meal increased dry matter and ether extract contents of trout dorsal fillet. The use of HI larvae meal induced a decrease of valuable polyunsaturated fatty acids (PUFA) even if differences were only reported at the highest level of HI inclusion. The insect meal worsened the lipids health indexes of the same muscle. Dietary inclusion of insect meal did not alter the villus height of the fish. No differences were found among treatments in relation to ADC of ether extract and gross energy, while ADC of dry matter and crude protein were higher in HI25 if compared to HI50. CONCLUSIONS: The obtained results showed that a partially defatted HI larvae meal can be used as feed ingredient in trout diets up to 40% of inclusion level without impacting survival, growth performance, condition factor, somatic indexes, dorsal fillet physical quality parameters, and intestinal morphology of the fish. However, further investigations on specific feeding strategies and diet formulations are needed to limit the observed negative effects of the insect meal on the FA composition of dorsal muscle.

Effects of dietary Tenebrio molitor meal inclusion in free-range chickens.

Insects are currently being considered as a novel protein source for animal feeds, because they contain a large amount of protein. The larvae of Tenebrio molitor (TM) have been shown to be an acceptable protein source for broiler chickens in terms of growth performance, but till now, no data on histological or intestinal morphometric features have been reported. This study has had the aim of evaluating the effects of dietary TM inclusion on the performance, welfare, intestinal morphology and histological features of free-range chickens. A total of 140 medium-growing hybrid female chickens were free-range reared and randomly allotted to two dietary treatments: (i) a control group and (ii) a TM group, in which TM meal was included at 75 g/kg. Each group consisted of five pens as replicates, with 14 chicks per pen. Growth performance, haematological and serum parameters and welfare indicators were evaluated, and the animals were slaughtered at the age of 97 days. Two birds per pen (10 birds/treatment) were submitted to histological (liver, spleen, thymus, bursa of Fabricius, kidney, heart, glandular stomach and gut) and morphometric (duodenum, jejunum and ileum) investigations. The inclusion of TM did not affect the growth performance, haematological or serum parameters. The morphometric and histological features were not significantly affected either, thus suggesting no influence on nutrient metabolization, performance or animal health. Glandular stomach alterations (chronic flogosis with epithelial squamous metaplasia) were considered paraphysiological in relation to free-range farming. The observed chronic intestinal flogosis, with concomitant activation of the lymphoid tissue, was probably due to previous parasitic infections, which are very frequently detected in free-range chickens. In conclusion, the findings of this study show that yellow mealworm inclusion does not affect the welfare, productive performances or morphological features of free-range chickens, thus confirming that TM can be used safely in poultry diets.

Fatty acid profile and cholesterol content of beef at retail of Piemontese, Limousin and Friesian breeds.

Samples of longissimus thoracis muscle of young bulls belonging to Piemontese (n=10), Limousin (n=11) and Friesian (n=10) breeds were analysed in order to study the chemical composition, fatty acids and cholesterol content of beef purchased at retail. The breeds and their differences in intramuscular fat content strongly influenced the fatty acids profile. The Piemontese animals displayed the lowest intramuscular fat and SFA content, while Friesian animals showed the highest intramuscular fat, SFA and MUFA content. In general, Limousin animals had intermediate characteristics. A higher PUFA proportion on total fatty acids was observed in Piemontese breed, but the PUFA absolute content (mg/100 g meat) did not differ among breeds. All the three breeds displayed a high content of n-6 fatty acids family and, consequently, a very unbalanced n-6/n-3 ratio. No differences were found for cholesterol content.

Geranylgeraniol prevents the cytotoxic effects of mevastatin in THP-1 cells, without decreasing the beneficial effects on cholesterol synthesis.

BACKGROUND AND PURPOSE: Statins, inhibitors of hydroxymethylglutaryl-CoA reductase, reduce the intracellular synthesis of cholesterol and prevent the onset of atherosclerosis. They also decrease the synthesis of isoprenoid molecules, such as the side chain of ubiquinone and geranylgeranyl pyrophosphate. As a consequence, statins impair mitochondrial metabolism and the activation of small monomeric GTPases (such as Rho and Ras), causing toxic effects. To date, a successful strategy to prevent statin toxicity is lacking. EXPERIMENTAL APPROACH: In human monocytic THP-1 cells, we measured the synthesis of cholesterol and isoprenoids, mitochondrial electron flow, the activity of RhoA and Rac, cell death and proliferation. KEY RESULTS: Mevastatin reduced the synthesis of cholesterol, geranylgeranyl pyrophosphate and ubiquinone, mitochondrial electron transport, activity of RhoA and Rac, and cell proliferation, accompanied by increased cell death. Geranylgeraniol, a cell-permeable analogue of geranylgeranyl pyrophosphate, reversed all these effects of mevastatin, without affecting its ability to reduce cholesterol synthesis. Notably, geranylgeraniol was more effective than the addition of exogenous ubiquinone, which rescued mitochondrial respiratory activity and reversed mevastatin cytotoxicity, but did not alter the decrease in cell proliferation. The same results were obtained in human liver HepG2 cells. CONCLUSIONS AND IMPLICATIONS: Geranylgeraniol had a broader protective effect against the cytotoxicity of statins than exogenous ubiquinone. Therefore, geranylgeraniol may be a more useful and practical means of limiting the toxicities of statins, without reducing their efficacy as cholesterol lowering agents.

Performances and meat quality of two Italian pig breeds fed diets for commercial hybrids.

The effects of specific diets for commercial hybrids were investigated on 6 Casertana and 11 Mora Romagnola, two endangered Italian pig breeds. Average daily gain (ADG), feed conversion index (FCI), dressing percentage and meat and fat quality of animals bred under similar environmental and nutritional conditions were compared to define their optimal slaughtering weight. Animals were fed the same diets assuming that requirements of Mora Romagnola and Casertana did not differ, and changed every 30kg of weight gain. ADG and FCI were calculated every 15 days. Weight gains, divided into 5 groups based on live weight (LW) of animals (⩽60kg, 60160kg), showed higher values for Casertana than Mora Romagnola, particularly from 121 to 160kg LW (687g/d). Average FCI from 50 to 160kg LW was similar in both breeds (4.2). After 403 days of trial, animals were slaughtered at about 195kg LW. Carcass measurements showed that Casertana had higher dressing percentage and lean cuts than Mora Romagnola. Both breeds showed extraordinary high ultimate pH values of M. longissimus thoracis (5.96 and 6.15 for Casertana and Mora Romagnola, respectively) M. semimembranosus (6.37 and 6.30), showing an incomplete post mortem glycolysis. Colour of M. longissimus thoracis did not differ between breeds and was particularly dark. Chemical analysis of Casertana meat showed lower percentage of water and fat; the total amount of fatty acids (SFA, MUFA and PUFA) and the SFA/UFA ratio did not show significant differences between breeds. Results showed that from a growth point of view the optimal slaughtering weight of Casertana and Mora Romagnola should not exceed 160kg LW. Both breeds had an uncommon reactivity to stress probably due to interactions of genetic, nutritional and management factors.

Effect of dietary clenbuterol and cimaterol on muscle composition, beta-adrenergic and androgen receptor concentrations in broiler chickens.

Illegal dietary supplementation with beta(2)-agonists has been shown to increase protein deposition and decrease fat accretion in domestic animals. In poultry the metabolic and endocrine responses to beta(2)-agonists are not fully elucidated. In this trial the effects of dietary clenbuterol (1 p.p.m.) and cimaterol (1 p.p.m.) on muscle composition and endocrine response of male broiler chickens were studied. Dietary clenbuterol induced a slight, but in general not significant, improvement of zootechnical performances and carcass yields. Chemical composition of muscle was not influenced by dietary treatments, even if a slight improvement of protein content was observed in treated groups. No effects on fatty acid composition of meat were detected. Both clenbuterol and cimaterol treatments caused a downregulation in testicular androgen receptors and in pulmonary, cardiac and central nervous system beta-adrenergic receptors.