The aim of the present thesis was to assess the effect of the dietary supplementation of SOD-rich melon pulp concentrate (MPC) on oxidative status, inflammation and growth performance of post-weaning piglets and poultry. With this purpose three different trials were conducted: 1) MPC administration to no challenge or LPS-challenged post-weaning piglets to evaluate changes in the oxidative status and inflammation markers in blood together with growth performance; 2) MPC administration to broilers to evaluate growth performance and the incidence of both pododermatitis and cellulitis; 3) expression of oxidative status genes in the liver in both piglets and chickens. During trial 1, forty-eight female piglets weaned at 24 days of age were divided in four homogeneous experimental groups of twelve animals each in a randomized block design and fed a basal diet (C, n. 24) or a basal diet plus 30 g/ton melon pulp concentrate (Melofeed®, Lallemand, Blagnac, France) (MPC, n. 24). The experimental trial lasted 29 days from weaning, performing a LPS challenge by injecting increased dosages four times every two days starting from 19th day of the experiment (19, 21, 23, 25 days) in half of C (n.12) and half of MPC (n.12) groups. Initial LPS dosage of 60 μg/kg of body weight was increased by 12% at each subsequent injection to reduce endotoxin tolerance. Growth performance including live body weight, feed intake, average daily gain and G:F were monitored from the beginning of the trial until the end of the experiment. Blood samples were collected to evaluate the antioxidant status of experimental animals by SOD activity (Superoxide dismutase), TAOC (Total Anti-Oxidant Capacity), ROS (Reactive Oxygen Species), Kit Radicaux Libres (KRL) test on blood, plasma and red blood cell (RBC), and 8-oxodGuo (8-oxo-7, 8-dihydro-2’-deoxyguanosine). Moreover blood samples were analysed for immune and inflammatory response by haptoglobin (Hp) and Cytokines IL-6, IL-1β, TNFα in serum. A positive effect of SOD-rich MPC was evidenced on FI and ADG (P<0.01; P=0.05 respectively), while LPS challenge significantly reduced both parameters in injected animals (P<0.01). Antioxidant status of MPC fed piglets was improved by higher TAOC levels (MPC=7.22 mM Trolox equivalent vs. C=4.54 mM Trolox equivalent; P<0.01) and RBC resistance to haemolysis (MPC=70.71 HT50, min vs. C=66.41 HT50, min; P≤0.01). No significant differences were evidenced for ROS, SOD activity and 8-oxodGuo in the four experimental groups. The challenge with LPS increased TNF-α, IL-1β, IL-6 (P<0.01) and Hp (P=0.03) levels in blood, but no differences were found for MPC administration. These results suggest that oral SOD supplementation by MPC increase some aspects of antioxidant status of post-weaning piglets with positive results on growing performance. In trial 2 a total of 1104 broilers were allocated to 4 experimental groups for 35 days with four different dietary treatments: a) basal diet (C: control), b) basal diet plus melon pulp concentrate (MPC1, MPC2 and MPC3) as described below. The feeding regimen consisted of starter (0-10 d), grower (11-24 d) and finisher diet (25-35 d). During starter phase, dietary treatments were corn-soybean meal based diets supplemented with 0 g/ton (C), 30 g/ton (MPC1), 15 g/ton (MPC2), 15 g/ton (MPC3) of melon pulp concentrate (MPC) (Melofeed®, Lallemand, Blagnac, France). In grower phase, C, MPC1 and MPC2 received same basal diet but MPC3 received basal diet supplemented with 15 g/ton of MPC. During 24-35 days, the same basal diet without MPC was supplied to four experimental groups. 12 pens per group with 23 broilers per pen were used. On day 24 and 25, pododermatitis was evaluated on all animals using a scoring system that ranged from 0 to 2. On day 35, cellulitis was evaluated on all slaughtered birds. Litter score and litter DM was assessed on day 35. Body weight (BW) of birds per pen was recorded on 0, 10, 24, 35 experimental days from the beginning of the experiment. Individual body weight, slaughter live body weight, carcass weight, dressing percentage and organs weight (liver, heart, intestine, Bursa of Fabricius, spleen and pancreas and gizzard) percentage were also assessed at day 35. Pen feed intake was recorded on 0, 10, 24, 35 experimental days. Pen feed residues were determined at the end of each feeding period to estimate mean ADG, ADFI and gain: feed (G:F) ratio for each pen. Treatment (MPC) was able to affect body weight (P<0.05), ADG (P<0.05) and G:F (P=0.05) during experimental period. Final BW was higher in MPC1 and MPC2 than C and MPC3 (P<0.01). Carcass weight tended to be higher in MPC2 than C and MPC3 (0.05<P≤0.1). Percentage of the Bursa of Fabricius weight tended to be higher (0.05<P≤0.1) in MPC1 and MPC3. Incidence and severity of pododermatitis varied within each feeding period. Significant treatment, time and their interaction (P<0.01) were found in pododermatitis lesions analysis. At 24 d of age, MPC3 scores were the highest (P<0.01) between diets. At 35 d of age, scores in MPC3 were still higher than MPC1 (P<0.05). Pearson correlation between pododermatitis and body weight was not significant, by the way it was highly significant (P<0.01) between pododermatitis and litter dry matter (-30%). No cellulitis was detected in experimental animals. These results suggest that oral SOD supplementation by MPC increases performance of poultry with a dose-dependent increase in pododermatitis incidence, but not significant effect on cellulitis occurrence. In the third trial liver tissue was collected from six piglets per treatment at the end of the trial 1 and 12 poultry per treatment at the end of grower phase (day 24) from trial 2 respectively. Collected samples were stored in liquid nitrogen for subsequent gene expression analysis by RT-PCR. β-actin and GAPDH of S. scrofa or G. gallus respectively were used as internal reference genes. GPx1, CAT and SOD1 were determined on piglet liver samples, while NFEL2L, CAT and SOD1 were determined on poultry hepatic tissue samples. Results from piglets’ trial showed that MPC, LPS challenge and MPC x LPS challenge interaction did not significantly affect liver gene expression of GPX1, CAT and SOD1 (P>0.05), with the exception of trend (P=0.09) for a down-regulation of CAT for MPC effect. Results from poultry trial showed that MPC did not significantly affect liver gene expression of NFEL2L in treated groups, while SOD1 expression showed a trend to reduce the down-regulation in MPC3 vs. C (P=0.09). CAT was significantly up-regulated in MPC3 than C and MPC1 (P=0.02). The obtained results show that MPC supplementation can directly affect CAT expression in the liver of poultry and challenged piglets and, to a lesser extent SOD1 in poultry. Results from the present thesis show that the inclusion of SOD-rich melon pulp concentrate in the diet of post-weaning piglets and poultry can significantly increase the blood levels of some antioxidant biomarkers and the expression of genes implicated in the regulation of the oxidative status in the liver.
|Titolo:||EFFECTS OF MELON PULP RICH IN SUPEROXIDE DISMUTASE ON PIGLETS AND POULTRY HEALTH|
|Supervisori e coordinatori interni:||SAVOINI, GIOVANNI|
|Data di pubblicazione:||18-dic-2015|
|Parole Chiave:||piglets; poultry; nutrition; antioxidants; gene expression|
|Settore Scientifico Disciplinare:||Settore AGR/18 - Nutrizione e Alimentazione Animale|
|Citazione:||EFFECTS OF MELON PULP RICH IN SUPEROXIDE DISMUTASE ON PIGLETS AND POULTRY HEALTH ; tutor: G. Savoini ; coordinatore: G. Savoini. - Milano : Università degli studi di Milano. DIPARTIMENTO DI SCIENZE VETERINARIE PER LA SALUTE, LA PRODUZIONE ANIMALE E LA SICUREZZA ALIMENTARE, 2015 Dec 18. ((28. ciclo, Anno Accademico 2015.|
|Appare nelle tipologie:||Tesi di dottorato|