Vanda Malfatto

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.

Morphometry, slaughtering performances, chemical and fatty acid composition of the protected designation of origin “Golden hump tench of Poirino highland” product

One hundred and thirty-two tench were photographed and a total of 13 landmarks were identified. Fish were grouped in four size classes on length basis and different shape descriptors were computed. Landmark configurations were superimposed. Size was computed as centroid size. The roundness coefficient, the log(partial area)/log(total area) ratio and the condition coefficient were calculated. Slaughtering performances and fillet composition analyses were performed. Shape variability was found primarily on cephalic area while head and tail regions were more homogeneous. A high correlation between centroid size and total length was found as well as a higher increase of the partial area than the total area justifying the hump shape of this tench. The scatter of relative warp 1 scores and centroid size for the four size classes has showed, with the increase of the length, a larger number of specimens that were characterised by a deep profile. Geometric morphometric approach produced a valuable tool in defining morphospaces for tench. Condition coefficient ranged from 1.24 to 1.29, without any significant difference among the size classes. Slaughtering performance resulted in agreement with those reported by other authors while VSI was lower. In fillets, the fatty acid profile was composed of about 30% of saturated fatty acids, 50% of monounsaturated fatty acids and 20% of polyunsaturated fatty acids with about 8% of docosahexaenoic acid. Atherogenic and thrombogenic indices were 0.58 and 0.42, respectively. Both n6/n3 and polyunsaturated/saturated fatty acids ratios were in accordance with value recommended for a healthy nutrition giving positive evaluation of the nutritional qualities of tench.

Effect of purple loosestrife (Lythrum salicaria) diet supplementation in rabbit nutrition on performance, digestibility, health and meat quality.

In this study, 160 Hycole weaned rabbits (35 days old) were randomly divided into four groups of 40. The rabbits were studied throughout a 54-day experimentation period in order to determine the impact of dietary supplementation from herbs composed of 0.2%, 0.4% dry ground Lythrum salicaria leaves (LS) and 0.3% Cunirel(®) (CR; a commercial herb mixture containing LS as the main ingredient) on performance, digestibility, health and meat quality. The basal diet was given to the control group. No significant differences were found in performance, 10 rabbits from each group were selected for evaluation regarding apparent digestibility. The rabbits fed the control diet and the diet with the low level of LS had a higher level of CP digestibility than did the animals that were supplemented with the high LS levels and CR (85.7% and 84.9% v. 84.0% and 84.0%, respectively; P<0.05). The ether extract digestibility was lower in the treatment group with 0.4%LS addition and CR as compared with the control group (52.2% and 54.5% v. 62.6%, respectively; P<0.05). The slaughter process was performed on 89-day-old rabbits to study the carcass characteristics, meat quality, blood parameters, caecal contents and gut histology. The total leukocyte counts in the control animals were lower than they were in the rabbits fed 0.2%, 0.4%LS and CR (4.06 v. 8.25, 8.63 and 8.21×10(9)/l, respectively; P<0.05). For caecal fermentation, the caecal contents of the rabbits fed 0.4% of LS, showed higher concentrations of total volatile fatty acid (VFA; 24.1 v. 18.9 mg/kg dry matter (DM); P<0.05) and acetic acid (18.3 v. 14.4 mg/kg DM; P<0.05), but lower ammonia levels (594 v. 892 mg/kg DM; P<0.05) as compared with the control group. PCR-denaturing gradient gel electrophoresis analyses were performed to evaluate the microbial community in hard faeces, collected at days 35, 42, 49, 56, 70 and 89, whereas the caecal contents were taken after slaughtering. The results demonstrated that between the treatment groups, the similarity of the microbial communities was higher as compared with the control group. Moreover, only age was shown to influence microbiota diversity. In conclusion, the results of this study indicated that supplementation of LS in rabbit diets leads to an increase in the total white blood cells, total VFA and acetic acid concentration, and a decrease in the ammonia levels, as well as the digestibility when CR and high level of LS were supplemented, without causing any adverse effects on other parameters.

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).

The establishment of a database of Italian feeds for the Cornell Net Carbohydrate and Protein System

Abstract A field application of the Cornell Net Carbohydrate and Protein System (CNCPS) in Italy has been limited because the feed bank is based on North American feedstuffs and still few laboratories are able to analyze feeds as requested by the CNCPS. Moreover, the standardization of analytical procedures is still not homogeneous among laboratories. This work was carried out to establish a first database for feeds commonly used in Italy, providing nutritionists and producers an accurate and current feed composition, also indicating methods and apparatus for analytical procedures potentially available for routine analysis. A total of 909 samples of hays, silages and raw materials (protein feeds, cereals and by-products) were analyzed through 1999 and 2002; analysis included protein solubility and degradability, protein fractions, structural carbohydrate fractions and the calculation of neutral detergent structural carbohydrates. When possible, average data were compared with those included in the feed bank of CNCPS ver. 3 and with those obtained by another Italian laboratory. The main differences were observed in chemical composition of forages and silages, whose composition largely depends on environmental conditions and physiological stage; protein feeds, cereals and by-products showed some differences in crude protein, soluble protein and protein fractions even in feeds of national origin. The intent to modify the feed bank values of CNCPS for establishing an Italian data base of feeds will require a collaborative study of many laboratories not only for forages, hays and silages samples - whose composition is greatly dependent on environmental factors and agronomic techniques - but also for protein fractions, whose values are largely influenced by even small changes in analytical techniques.

Use of natural extract of chestnut (Silvafeed ENC®) in broiler feeding: effect on growth performance

Abstract The aim of this research was to study the effect of addition of natural extract of chestnut (Castanea sativa) Silvafeed ENC® in commercial feed on the growth of broilers. Two hundred and four broiler chicks (Cobb 508) 14 d old male, were randomly assigned to 12 floor pens and fed commercial diet supplemented with 0% (CE0), 0.15% (CE15), 0.20% (CE20) and 0.25% (CE25) of ENC. The ENC addition showed a beneficial effect on weight increases daily feed intake (DFI) and average daily gain (ADG) from 14 to 35 days of age. In the second half of trial the effects were less evident and concluding with a detrimental effect in CE25 group. Feed conversion rate (FCR) appears to be statistically different in the second and fifth weeks of feeding. The inclusion of ENC at 0.20%, (CE20) had significant influences on final weight, DFI and ADG and a favourable influence on FCR in comparison with the other three groups. In conclusion, ENC has been shown to be beneficial at concentrations between 0.15% and 0.20%.

Milk yield and quality of Aosta cattle breeds in Alpine pasture

Riassunto Produttività e qualità del latte di razze bovine valdostane in alpeggio. Lo studio riferisce sulla produttività e qualità del latte di bovine di razza Pezzata Rossa, Pezzata Nera e Castana Valdostana, allevate in dieci alpeggi della Valle d’Aosta. Sono state studiate le caratteristiche del latte individuale prelevato in momenti rappresentativi della fase di pascolamento estivo. I risultati confermano l’elevato grado di adattabilità delle lattifere anche in condizioni climatiche di particolare difficoltà (stagione estiva 2003); tuttavia, la composizione acidica del latte segnala un significativo calo dei PUFA in coincidenza del peggioramento della qualità dell’erba dei pascoli.

Nutritive Value and Energy Content of the Straw of Selected Vicia L. Taxa from Tunisia

The chemical composition and energy value of straws of Vicia sativa L. (varieties Languedoc and Mghila, and subspecies amphicarpa) and Vicia villosa Roth. (variety Sejenane and accession 2565) were investigated. The plants were grown in a Mediterranean environment, under identical environmental conditions. Total digestible nutrients (TDN) and energy values (digestible energy, metabolisable energy, and net energy for lactation) were estimated according to the equations developed by the 2001 Dairy National Research Council. Both ether extract (EE) or total fatty acids (FA) amounts, and digestible neutral detergent fibre (dNDF) calculated from chemical analysis or measured using a 48-hour rumen in vitro assay were used for calculations. Significant differences were observed in the chemical composition and energy value of the straws of the considered V. sativa and V. villosa varieties. Within the same variety, the TDN was similar using either EE or FA values for calculation. The energy resulted largely dependent on the dNDF values. Energy was higher when in vitro dNDF was used for calculation in low-NDF straw samples, while the opposite occurred for high-NDF samples.