Luca Carraro

Dietary supplementation with olive stone meal in growing rabbits

Abstract Olive stone meal is a low-digested fibre source potentially useful in the prevention of digestive troubles in growing rabbit permitting a better balance of dietary fibre fractions. To evaluate its efficacy, three experimental diets containing 0, 3 or 6% olive stone meal were fed to 222 rabbits from weaning (28 d) to slaughter (73 d). Olive stone inclusion increased the proportion of large dietary particles while did not affect growth performance, digestive physiology and carcass and meat quality. Due to optimum health status observed in all experimental groups, the preventive action of olive stone meal against the occurrence of digestive troubles was not proven.

Replacing starch with digestible fibre in growing rabbit feeding

Abstract To evaluate the effect of replacing dietary starch with digestible fibre (DF=pectin and hemicelluloses) on health status, digestive physiology, growth performance, and carcass traits, 250 hybrid rabbits weaned at 27 d were fed until slaughter (76 d) five diets with increasing DF to starch ratio (1.0 to 1.9; DF 18.9 to 22.2%; starch 19.6 to 11.5%). The digestibility of dry matter (64.7, 65.2, 66.8, 67.5 and 67.6%) and NDF (27.9, 32.2, 35.0, 40.2 and 41.5%) increased (probability of linear component of variance, L<0.001) with increasing DF to starch ratio. Final live weight and daily growth tended to decrease (L=0.06), feed intake significantly lowered (130 to 122 g/d, L=0.01) and feed conversion ratio improved (2.72 to 2.68; L<0.01). Health status, caecal fermentation and ileal mucosa traits of rabbits did not change. The feeding strategy failed in controlling the diffusion of epizootic rabbit enteropathy.

Digestible fibre to ADF ratio and starch level in diets for growing rabbits

Abstract To evaluate the effect of digestible fibre (DF, hemicelluloses+pectins)/ADF ratio (1.0 and 1.3) and starch level (12, 15, and 18%) on health status, digestive physiology, growth performance, and carcass traits, 246 rabbits weaned at 27 d were fed until slaughter (76 d) with six diets formulated according to a bifactorial arrangement (2 DF/ADF ratios by 3 starch levels). Increasing DF/ADF improved DM digestibility (P<0.01), but did not affect growth performance, caecal content characteristics and slaughter traits. Increasing starch level improved digestibility efficiency and conversion index (P<0.001), decreased ileal mucosa villi height (P=0.04), without affecting growth performance, caecal fermentation and slaughter results. The increase of DF/ADF ratio tended to reduce mortality (25.0 vs 17.6%; P=0.11), whereas the raise of starch greatly increased mortality (from 6.9 to 43.1%; P<0.001) and sanitary risk (from 13.9 to 63.9%; P<0.001).

Dietary supplementation of butyrate in growing rabbits

Riassunto Integrazione alimentare con butirrato in conigli in accrescimento. L’effetto dell’inclusione di butirrato nella dieta è stato valutato in 220 conigli svezzati a 28 d e alimentati fino alla macellazione (70 d) con diete sperimentali contenenti 0, 0,5, 1,0 e 2,0 g/kg di butirrato sodico. L’integrazione con butirrato ha diminuito la digeribilità della sostanza secca (P<0,01) e ha tendenzialmente aumentato (P<0,10) l’accrescimento (48,5 vs. 50,0 g/d) e il consumo alimentare, ma non ha modificato l’attività fermentativa ciecale e le caratteristiche della mucosa intestinale a 42 d di età, né la qualità della carcassa e della carne alla macellazione. L’inclusione di butirrato ha rallentato la comparsa di una grave colibacillosi, ma non ha consentito di evitare il trattamento antibiotico, senza effetti significativi su mortalità e morbilità nell’intera prova. In conclusione, l’inclusione di butirrato non ha sostanzialmente influenzato le prestazioni produttive, la fisiologia digestiva, lo stato sanitario e la qualità della carne.

Effect of progressive reduction in crude protein and lysine of heavy pigs diets on some technological properties of green hams destined for PDO dry-cured ham production

In order to investigate the effects of dietary crude protein (CP) and lysine (Lys) content on some technological properties of green hams destined for Protected Designation of Origin (PDO) dry-cured ham, green hams visual appraisal scores, thickness, iodine number and fatty acid composition of subcutaneous fat, and ham weight losses during seasoning (SL) were assessed. The green hams were obtained from 233 pigs fed four diets containing 140 to 110g/kg CP and 6.5 to 5.3g/kg total Lys from 90 to 165kg body weight. A reduction in dietary CP and Lys of up to 20% compared with conventional feeds led to a 15% increase in the thickness of the subcutaneous fat, a 5% decrease in linoleic and polyunsaturated fatty acids in subcutaneous fat and a 7% decrease in SL. A 20% reduction of CP and Lys in diets for finishing pigs has positive effects on the technological properties of green hams destined for PDO dry-cured ham production.

Growth performance, carcass traits and meat quality of growing pigs on different feeding regimes slaughtered at 145 kg BW

Abstract This study investigated the effects of feeding regime on growth performance, carcass traits and meat quality of pigs slaughtered at around 145 kg BW. A total of 96 barrows housed in eight pens were allotted to three groups in each pen. One group was fed ad libitum (AL) and the others were fed according to two quasi AL feeding regimes adjusting feed allowances with increasing BW. At slaughterhouse, the weights of the main lean and fat cuts were recorded, and a sample of longissimus lumborum (LL) was taken for physical and chemical analyses. Average daily gain (ADG) approached 940 g d−1, and gain to feed ratio (G:F) was close to 0.38. Compared with the AL-feeding regime, the feed restriction reduced the pigs’ ADG (−3.5%), feed intake (−7.4%) and carcass weight (−3%) (p < 0.01), but improved their G:F (+ 4%, p < 0.01). Feeding regime did not affect meat quality traits and exerted only minor effects on the weight of primal cuts and on the fatty acid composition of the intramuscular fat of the LL. However, AL-fed pigs tended to yield heavier fat cuts and showed a greater proportion of saturated fatty acid in the LL when compared to restricted feed barrows. In conclusion, moderate restriction in the feeding of medium–heavy pigs seems advisable, as it improves feed efficiency and could cut feed costs compared with the AL-feeding regime without affecting carcass and meat characteristics.

Poly-chlorinated biphenyls (PCB) in European sea bass from different rearing systems

Abstract The chemical composition and the level of seven indicator congeners of PCB (BZ/IUPAC no. 28, 52, 101, 118, 138, 153, and 180) were determined in 133 specimens of farm-raised European sea bass (Dicentrarchus labrax). The fish were caught from different aquaculture rearing systems: extensive fish valley, semi-intensive ponds, sea-cages, and intensive concrete tanks. Fresh fillet chemical composition differed among the rearing systems (fat: 2.9, 7.5, 7.1, and 9.4%; P<0.001). Total concentrations of indicator congeners were below the EU limit (200ng/g fat) for meat, poultry and eggs, being the lowest in extensively-reared sea bass (75ng/g fat), intermediate in sea bass from semi-intensive ponds (119) and sea cages (116), and the highest in intensively-reared fish (133) (P<0.001). Similarly, PCB concentrations in fresh fillets were 2,438, 10,116, 8,491, and 12,952pg/g in the four systems (P<0.001). The congener 153 was the most represented in all rearing systems. TEQ concentrations for the dioxin-like congener no. 118 were 50 to 200 times lower than the maximum admitted value. Total concentration of indicator congeners of PCB was poorly correlated with fish slaughter weight (R2=0.17), while highly correlated with fat concentration of fish (R2=0.75).

Effects of feed allowance and indispensable amino acid reduction on feed intake, growth performance and carcass characteristics of growing pigs

The hypothesis that pigs placed on diets with reduced indispensable amino acid (AA) content attempts to offset the reduction in the nutrient density with increased feed intake was tested. In the experiment, feeds with a high or a low AA content were administrated to pigs fed ad-libitum or restrictively according to a 2 × 2 factorial design. Ninety-six barrows were housed in 8 pens (12 pigs/pen) equipped with automatic feeders. Within pen, and from 47 body weight (BW) onwards, 6 pigs were fed ad libitum. The others pigs were allowed to consume, as a maximum, the feed amounts indicated by the breeding company feeding plane to optimize the feed efficiency. In early (86–118 kg BW) and late (118–145 kg BW) finishing, the pigs of 4 pens received feeds with high indispensable AA contents (8.1 and 7.5 g lysine/kg in the two periods, respectively). The other pigs received feeds with reduced indispensable AA contents (lysine, methionine, threonine and tryptophan) by 9 and 18% in early and late finishing, respectively. Body lipid and protein (Pr) retentions were estimated from BW and back-fat depth measures recorded at the beginning and the end of each period. Nitrogen excretion was estimated as actual intake minus estimated N-retention (Pr/6.25). Pigs were slaughtered at 144 kg BW. Restricted feeding decreased feed intake (-7%), daily gain (-5%), carcass weight (-2.6%) and back-fat depth (-8.0%) but increased gain:feed ratio (+2%). The AA restriction increased feed intake (+5.9%), carcass weight (+4.9%) and intramuscular fat (+17.6%), and reduced carcass weight variation (-36%), with no effects on the feed efficiency and the estimated Pr (142 g/d). N excreted was reduced by feed (-9%) and dietary AA (-15%) restrictions. Irrespectively of the feeding level, the pigs responded to a reduction of the dietary essential AA content by increasing their feed intake.

Effect of pre-slaughter conditions in European sea bass (Dicentrarchus labrax)

Riassunto Effetto delle condizioni pre-macellazione in spigole (Dicentrarchus labrax). Allo scopo di valutare l’effetto delle condizioni pre-macellazione sulla qualità e la freschezza durante la conservazione, 210 spigole sono state poste in vasche a bassa densità (20 kg/m3) e ad alta densità (80 kg/m3). Entro densità, le sp gole sono state macellate dopo 2 o 24 h. La densità nelle vasche pre-macellazione ha influenzato marginalmente gli indicatori fisiologici di stress e le variabili di freschezza. L’aumento dell’attesa pre-macellazione da 2 a 24 h non ha modificato il livello plasmatico di cortisolo, ha ridotto la glicemia e ha influenzato negativamente alcun indici di freschezza. Nel complesso, tuttavia, la qualità e la freschezza del pesce durante la conservazione non sono state sostanzialmente modificate dalle condizioni di pre-macellazione.