Showing papers by "Gerolamo Xiccato published in 2008"

Alternative stress indicators in sea bass Dicentrarchus labrax, L.

Abstract: Stress indicators (plasma cortisol, glucose and lactate) were evaluated in sea bass Dicentrarchus labrax submitted to different pre-slaughter conditions, and cortisol levels in plasma were found to correlate with those detected in mucus, gut contents and muscle. The results demonstrate new possibilities for monitoring stress status in fishes in which blood sampling is difficult or impossible.

Effect of cage floor and stocking density on growth performance and welfare of group-housed rabbits.

Abstract: Two hundred forty rabbits weaned at 36 d (LW=1103±4 1 g) were housed in groups to evaluate the effect of stocking density and type of cage floor o n behaviour, health status, growth performance, and carcass and meat quality. The rabbits were put in g roups of 6 into 40 cages of two sizes (78 x 64 cm o r 58 x 64 cm) corresponding to two stocking densities (D12, 12.1 rabbits/m vs. D16, 16.2 rabbits/m ). Within density, four types of floor were compared ( steel slat, plastic slat, wire net and straw litter on wire net) according to a 2 x 4 factorial arrangemen t with five replications (cages). The rabbits were fed a unique diet (CP: 15.8%, ADF: 19.3%, DE: 9.8 MJ/kg ). No antibiotic was added to feed or water. Rabbit reactivity was assessed by the tonic immobil ity and open-field tests at 70 and 74 d of age. Rabbits were slaughtered at 78 d to evaluate carcas s and meat quality. Femur dimensions and resistance to fracture were measured. Sanitary stat us and growth performance were highly satisfying in all treatments: growth rate averaged 45.5 g/d and f inal weight 2967 g, with a feed conversion rate of 3.49. Stocking density did not affect growth perfor mance, meat quality, nor animal reactivity. In contrast, the type of floor significantly affected growth performance: rabbits kept on straw bedded floor showed the lowest final weight (2865 g vs. 30 00 g on average, P=0.03), weight gain and feed intake. Differences in carcass and meat quality mai nly depended on the weight at slaughter: dressing percentage and separable fat of the carcass were lo wer (P<0.01) in the lightest rabbits kept on straw (58.6% and 2.3%, respectively) compared to the heav ier animals of the other three experimental groups (average values 59.9% and 3.0%, respectively ). The type of floor also affected animal reactivity: the number of attempts necessary to ind uce immobility, considered inversely correlated with fear towards humans, was lower in rabbits kept on straw; these rabbits also showed a more passive reaction during the open field test, spendi ng less time exploring and more time in an immobile state (P<0.01) in comparison with the animals house d in the cages with plastic slat or wire net floors .

Digestible fibre to starch ratio and antibiotic treatment time in growing rabbits affected by epizootic rabbit enteropathy.

Abstract: The study aimed to evaluate if the digestible fibre (DF, hemicelluloses+pectins) to starch ratio of th e diet and the time of antibiotic treatment after epi zootic rabbit enteropathy (ERE) outbreak affect hea lt status, digestive physiology, growth performance, a nd carcass traits of early weaned rabbits. Two hundred forty Grimaud hybrid rabbits were put in in dividual cages and controlled from 25 d of age to slaughter (70 d). The rabbits were assigned to four groups according to a 2x2 factorial arrangement (2 DF to starch ratios by 2 antibiotic treatment times ). Half of the rabbits fed ad libitum diet L, with low (1.0) DF to starch ratio (19.1% DF and 18.9% starch s-fed) and half fed diet H with high (2.5) DF to starch ratio (23.9% DF and 9.6% starch). The diets were characterized by similar protein (16.8%), ADF (19.8%), and ADL (3.9%) concentrations. After t he ERE appearance, half of the rabbits within diet were submitted to an early antibiotic treatmen t (from 38 to 42 d of age), while half of the rabbi ts to a late treatment (from 45 to 49 d). The antibiot c treatment was realized by an association of oxytetracycline hydrochloride (100 g/100 l) and col istin (24 g/100 l) administered in water. At 43 d o f age, 36 rabbits (6 per group) were sacrificed to co lle t caecal content and ileum mucosa samples. Increasing DF to starch ratio of the diet improved fibre fraction digestibility (P<0.001) therefore maintaining a similar nutritive value (digestible e nergy=10.7 MJ/kg) among diets. Mortality (31.7% vs. 11.5%) and morbidity (38.5% vs. 18.5%) signific antly decreased (P<0.001) by increasing DF to starch ratio, thus reducing sanitary risk by two th irds. These results were apparently associated to a higher caecal fermentation activity (volatile fatty acids: 49.6 vs. 60.7 mmol/l; P=0.03) in rabbits fe d the high DF to starch diet, while ileal mucosa morp h metry was unaffected. Once the health status was recovered, growth performance and slaughter res ults were scarcely affected by the dietary treatments. An early antibiotic treatment, administ ered within one week from the first ERE symptoms, reduced mortality (17.3 vs. 26.0%; P=0.07) and impr oved growth performance and slaughter results in comparison with a later treatment. Even the early a ntibiotherapy did not avoid that rabbit mortality reached a level unacceptable for a commercial farm, however. The association of a diet with a high DF to starch ratio and an early antibiotic treatment p ermitted to maintain the mortality at a basic level (5.8%) and provided the best growth performance and c rcass quality.