Manuela Renna

Tenebrio Molitor Meal in Rainbow Trout (Oncorhynchus Mykiss) Diets: Effects on Animal Performance, Nutrient Digestibility and Chemical Composition of Fillets

This study evaluated the effects of diets containing Tenebrio molitor (TM) larvae meal on growth performances, somatic indexes, nutrient digestibility, dorsal muscle proximate and fatty acid (FA) compositions of rainbow trout. Three hundred sixty fish were randomly divided into three groups with four replicates each. The groups were fed diets differing in TM inclusion: 0% (TM0), 25% (TM25) and 50% (TM50) as fed weight basis. Weight gain was not affected by treatment. Feeding rate was significantly higher in TM0 than TM50. Feed conversion ratio was significantly higher in TM0 than TM25 and TM50, while an opposite trend was observed for protein efficiency ratio and specific growth rate. The survival rate was significantly lower in TM0 than TM25 and TM50. The apparent digestibility of protein was significantly lower in the TM50 group than the other groups, while the apparent digestibility of dry matter, organic matter and lipids was unaffected by treatment. If compared to control, the protein and lipid contents of fillets were respectively increased and decreased following TM inclusion in the diet. The Σn3/Σn6 FA ratio of fish dorsal muscle was linearly (TM0>TM25>TM50) reduced by TM inclusion in the diet. Results suggested that TM could be used during the growing phase in trout farming; however, additional studies on specific feeding strategies and diet formulations are needed to limit its negative effects on the lipid fraction of fillets.

Fatty Acid Composition of the Seed Oils of Selected Vicia L. Taxa from Tunisia

Whole mature seeds of eight selected varieties, subspecies and accessions of three Vicia L. species grown in Tunisia were investigated for their fatty acid (FA) profile. The FA composition ranged from lauric (C12:0) to lignoceric (C24:0) acids. The total FA content was 1235.14 to 1580.34 mg 100 g–1 dry matter (DM). Linoleic acid (C18:2 c 9c 12; 647.87 to 801.93 mg 100 g–1 DM, i.e. >50% of total FA), oleic acid (C18:1 c 9; 181.32 to 346.79 mg 100 g–1 DM, i.e. 13.2 to 24.6% of total FA) and α-linolenic acid (C18:3 c 9c 12c 15; 42.01 to 97.72 mg 100 g–1 DM, i.e. 3.4 to 7.1% of total FA) were the most abundant unsaturated FA. Palmitic acid (C16:0; 189.86 to 281.07 mg 100 g–1 DM, i.e. 15.4 to 17.8% of total FA) and stearic acid (C18:0; 24.35 to 52.75 mg 100 g–1 DM, i.e. 2.0 to 4.0% of total FA) were the major saturated ones. The sum of all other FA did not exceed 3.0% of TFA. The favourable FA profile of the studied vetch seeds makes them interesting cheap diet components to be used in the nutrition of ruminants and non-ruminants reared in the dryland agricultural regions of Mediterranean countries.

Relationships between botanical and chemical composition of forages: a multivariate approach to grasslands in the Western Italian Alps

BACKGROUND Plant composition of species-rich mountain grasslands can affect the sensorial and chemical attributes of dairy and meat products, with implications for human health. A multivariate approach was used to analyse the complex relationships between vegetation characteristics (botanical composition and plant community variables) and chemical composition (proximate constituents and fatty acid profile) in mesophilic and dry vegetation ecological groups, comprising six different semi-natural grassland types in the Western Italian Alps. RESULTS Mesophilic and dry grasslands were comparable in terms of phenology, biodiversity indices and proportion of botanical families. The content of total fatty acids and that of the most abundant fatty acids (alpha-linolenic, linoleic and palmitic acids) were mainly associated to nutrient-rich plant species, belonging to the mesophilic grassland ecological group. Mesophilic grasslands showed also higher values of crude protein, lower values of fibre content and they were related to higher pastoral values of vegetation compared to dry grasslands. The proximate composition and fatty acid profile appeared mainly single species dependent rather than botanical family dependent. CONCLUSION These findings highlight that forage from mesophilic grasslands can provide higher nutritive value for ruminants and may be associated to ruminant-derived food products with a healthier fatty acid profile.

Milk yield, gross composition and fatty acid profile of dual‐purpose Aosta Red Pied cows fed separate concentrate‐forage versus total mixed ration

This study was designed to evaluate the effects of two feeding methods on milk yield, composition and fatty acid (FA) profile obtained from dual-purpose cattle. Twenty-four Aosta Red Pied cows beyond peak of lactation were assigned to two groups and fed hay and concentrates in the proportions 0.69 and 0.31 on a dry matter basis for 10 weeks. Concentrates were offered separately from forages 6 times a day (separate ration, SR) or as a total mixed ration (TMR). The feeding method did not significantly influence dry matter intake (16.8 vs. 16.9 kg/head/day for SR- and TMR-fed cows, respectively), milk yield (17.4 vs. 17.5 kg/head/day), milk fat, protein and lactose contents (36.4 vs. 35.2, 33.5 vs. 32.8, and 47.3 vs. 47.4 g/kg) and yields (607.9 vs. 613.4, 567.4 vs. 572.7 and 805.5 vs. 829.7 g/head/day). The overall milk FA profile was very similar between groups. Milk concentrations of FA used as indirect markers of rumen function (C18:2 t10c12, odd- and branched-chain FA) and the extent of ruminal biohydrogenation were comparable (P > 0.05) between SR- and TMR-fed cows, suggesting that ruminal pH did not vary considerably as a consequence of the feeding strategy applied.

Effect of Breed, Cage Type, and Reproductive Phase on Fecal Corticosterone Levels in Doe Rabbits

Fecal corticosterone concentration (FCC) is increasingly being used as a noninvasive indicator of stress in assessment of nonhuman animal welfare. The aim of this study was to evaluate effects of breed, cage type, reproductive phase, and their interactions on FCC levels in doe rabbits. A total of 252 doe rabbits were randomly assigned to 2 groups. Does were individually housed in either standard dimension cages (SC) or in cages with a volume more than double that of the SC. Bigger cages (BC) were equipped with a plastic foot mat. Breed, cage type, and reproductive phase significantly affected FCC. New Zealand hybrids showed higher FCCs (p < .001) when compared witho the autochthonous breed (27.77 ± 0.47 vs. 24.61 ± 0.36 pg g−1, respectively). Increased cage size coupled with a plastic foot mat resulted in a significant decrease in doe FCC. The highest FCCs were detected at partum (BC: 30.40 ± 0.81 pg g−1; SC: 33.36 ± 0.86 pg g−1; p ≤ .05), followed by postweaning (BC: 25.09 ± 0.95 pg g−1; SC: 27.63 ± 0.95 pg g−1; p ≤ .05). These results support the hypothesis that measurement of FCC provides a useful indicator of chronic stress in doe rabbits.

Comparing milk yield, chemical properties and somatic cell count from organic and conventional mountain farming systems

Abstract A study was undertaken to investigate the effects of farming systems (organic vs. conventional), diet (hay/concentrate vs. pasture) and their interaction on milk yield, gross composition and fatty acid (FA) profile of dairy cows bred in mountainous areas. For this purpose four dairy farms (two organic and two conventional) were chosen in the alpine territory of Aosta Valley (NW Italy); individual milk yield was recorded daily and bulk milk samples were collected monthly from February to September 2007 to cover dietary variations. Higher levels of milk production (P<0.05) and lower milk protein amounts (P<0.01) were observed in the organic farms with respect to the conventional ones, while no significant differences were noticed in milk fat and lactose contents and in somatic cell count. Concerning fatty acids, only small differences were detected between organic and conventional milk and such differences seemed to be related mainly to the stabled period. Diet affected almost all variables studied: pasture feeding provided a significant improvement in the fatty acid composition in both organic and conventional systems leading to lower hypercholesterolemic saturated fatty acids, higher mono- and polyunsaturated fatty acids and conjugated linoleic acid amounts (P<0.001).

Yellow mealworm larvae (Tenebrio molitor) inclusion in diets for male broiler chickens: effects on growth performance, gut morphology, and histological findings

Abstract This study evaluated the effects of Tenebrio molitor (TM) larvae meal inclusion in diets for broilers. A total of 160 male broiler chicks (Ross 708) at one‐day of age were randomly allotted to four dietary treatments: a control (C) group and three TM groups, in which TM meal was included at 50 (TM5), 100 (TM10), and 150 (TM15) g/kg, respectively. The experimental diets were isonitrogenous and isoenergetic. Each group consisted of five pens as replicates (8 chicks/pen). After the evaluation of growth performance and haematochemical parameters, the animals were slaughtered at 53 days and carcass traits were recorded. Morphometric investigations were performed on duodenum, jejunum, and ileum and histopathological alterations were assessed for liver, spleen, thymus, bursa of Fabricius, kidney, and heart. The live weight (LW) showed a linear (12 and 25 days, P < 0.001 and P < 0.05, maximum with TM15 and TM10) and quadratic (53 days, P < 0.05, maximum with TM5) response to dietary TM meal inclusion. A linear (1 to 12 and 12 to 25 days, P < 0.001, maximum with TM15) and quadratic (12 to 25 days, P = 0.001, maximum with TM15) effect was also observed for the daily feed intake (DFI). The feed conversion ratio (FCR) showed a linear response (25 to 53 and 1 to 53 days, P = 0.001 and P < 0.05, maximum with TM15). Haematological and serum biochemical traits, carcass traits and histopathological findings were not affected by dietary TM meal inclusion (P > 0.05). TM15 birds showed lower villus height (P < 0.05), higher crypt depth (P < 0.05), and lower villus height to crypt depth ratio (P = 0.001) compared with C and TM5. In conclusion, increasing levels of dietary TM meal inclusion in male broiler chickens may improve body weight and feed intake, but negatively affect feed efficiency and intestinal morphology, thus suggesting that low levels may be more suitable. However, no effect on haematochemical parameters, carcass traits, and histological findings were observed in relation to TM meal utilization.

Effect of rearing substrate on growth performance, waste reduction efficiency and chemical composition of black soldier fly (Hermetia illucens) larvae: Rearing substrate effects on performance and nutritional composition of black soldier fly

BACKGROUND Wastes can be used as rearing substrate by black soldier fly (BSF) larvae, the latter being exploitable as a protein source in animal feed. This research aimed to assess the influence of four rearing substrates (Trial 1 (organic wastes): a mixture of vegetable and fruit (VEGFRU) vs. a mixture of fruits only (FRU); Trial 2 (agro-industrial by-products): brewery (BRE) vs. winery (WIN) by-products) on BSF larvae development, waste reduction efficiency and nutritional composition. RESULTS If respectively compared to FRU and WIN, VEGFRU and BRE larvae needed less time to reach the prepupal stage (22.0, 22.2, 20.2 and 8.0 days of trial, respectively) and had higher protein content (229.7, 257.3, 312.9 and 395.7 g kg-1 dry matter). The waste reduction index ranged from 2.4 (WIN) to 5.3 g d-1 (BRE). BRE larvae showed the lowest saturated and the highest polyunsaturated fatty acid proportions (612.4 and 260.1 g kg-1 total fatty acids, respectively). CONCLUSION Vegetable and fruit wastes and winery by-products can be used as rearing substrates for BSF larval mass production. Brewery by-products led to very promising larval performance and nutritional composition. However, given BRE limited availability, low BRE dietary inclusion levels could be used with the purpose of increasing larval performance.

Bilberry pomace in growing rabbit diets: effects on quality traits of hind leg meat

Abstract The aim of the present study was to evaluate the effects of dietary bilberry pomace (BP) on colour, cooking losses, proximate composition and fatty acid (FA) profile of hind leg meat in growing rabbits. One hundred and forty-four Grimaud weaned rabbits (35 days old) were randomly divided into four groups of 36 animals each and fed ad libitum with a basal diet (C diet) tested against three assay diets developed by substituting 50, 100 and 150 g/kg of the C diet with BP (BP5, BP10 and BP15 diets, respectively). At 83 days of age, the rabbits were slaughtered without fasting. Inclusion of BP in the diet did not significantly affect colour, cooking losses, ash and protein contents, but determined a significant increase of ether extract in the muscle. Increasing dietary inclusion of BP also determined a proportional increase of total polyunsaturated fatty acids (PUFA) and total n-3 FA, as well as a proportional decrease of total saturated fatty acids (SFA), total branched chain fatty acids (BCFA) and total monounsaturated fatty acids (MUFA) in the muscle. Dietary BP significantly improved the PUFA/SFA ratio, the Σ n-6/Σ n-3 FA ratio and the atherogenicity, thrombogenicity and hypocholesterolemic/hypercholesterolemic FA indexes of rabbit meat but it decreased Δ5-desaturase plus Δ6-desaturase index. The obtained results suggest that BP inclusion in growing rabbit diets can improve the fatty acid profile of hind leg meat, with consequent health benefits to consumers.

Effect of Cage Type on Fecal Corticosterone Concentration in Buck Rabbits During the Reproductive Cycle

Fecal corticosterone concentration (FCC) was measured in 14 buck rabbits individually housed in standard-dimension cages (SC) or in bigger cages (BC; with a volume more than double that of SC and equipped with a plastic foot mat) during 4 consecutive reproductive cycles. Cage type and reproductive phase (estrous synchronization of doe rabbits, artificial insemination, partum, preweaning, and postweaning) were not statistically significant but tendentially affected FCCs (.05 < p < .10). Buck rabbits housed in SC showed higher FCCs than those housed in BC (27.42 pg g− 1 dried feces and 25.57 pg g− 1, respectively; SEM = 2.952). The highest FCC values were detected at artificial insemination (BC, 27.91 pg g− 1; SC, 30.45 pg g− 1; SEM = 3.520), highlighting that the phase of semen collection could be one of the most critical moments for buck rabbits, although further investigations are needed. These preliminary results suggest that measurement of FCC could be used as an indicator of chronic stress in buck rabbits.