G. Pastorelli

Influence of dietary fat, on fatty acid composition and sensory properties of dry-cured Parma ham.

A feeding trial with 27 pigs was performed in order to estimate the effect of different dietary fats on the fatty acid composition, flavour and sensory properties of dry-cured Parma hams, ripened for 16 months. The animals received a pelleted diet supplemented with different fat sources: tallow (TA), corn oil (CO), and rapeseed oil (RO). The sensory quality of the hams was evaluated by means of sensory analyses and by instrumental procedures such as gas chromatography-mass spectrometry of the volatile aroma compounds. A treatment effect was detected for linolenic acid in RO vs. CO and TA hams (P<0.01) and for MUFA content (P<0.01) that was higher in RO and TA compared with CO. The results of panel test showed a significant difference (P<0.05) between TA vs. CO and RO hams. Volatile compounds showed limited differences even if in CO group the amount of singular compound is higher than TA and RO.

Oxidative status of plasma and muscle in rabbits supplemented with dietary vitamin E

Thirty New Zealand white rabbits, mean weight 2 kg, were divided into three equal groups balanced for body weight and randomly assigned to a diet containing 60 (C), 150 (T1) or 375 (T2) mg/kg of all-rac-alpha-tocopheryl acetate. After 29 days, the animals were slaughtered. alpha-Tocopherol was assayed in muscle (longissimus dorsi) and plasma; triglycerides and cholesterol (total, high density lipoprotein, low density lipoprotein) were analysed in plasma; reactive oxygen metabolites (ROMs) were analysed in serum; and thiobarbituric acid-reactive substances (TBARS) were analysed in muscle. There were no body weight and food intake differences between the groups. The plasma vitamin E and vitamin E:lipid ratio were significantly higher in groups T1 and T2 than in C, but increases were not linearly related to dietary levels. Muscle alpha-tocopherol concentrations in the treated groups were significantly higher than in C, and linearly related (R =.67) to the vitamin E:lipid ratio. ROM and vitamin E levels in blood were inversely related (R =.74), with ROMs significantly lower in the treated groups than in C. The 60-mg/kg dose of C recommended by the National Research Council was unable to control ROM production. Lipid oxidation in muscle was significantly lower in T2 than in the other groups, and TBARS correlated significantly with muscle vitamin E (R =.61) and serum ROM (R =.73). These data suggest that vitamin E supplemented at 375 mg/kg diet can effectively control ROM production and improve muscle lipostability. ROM assay provides a useful indirect estimate of the oxidative status of muscle in vivo.

Influence of dietary conjugated linoleic acids and vitamin E on meat quality, and adipose tissue in rabbits

Eighty New Zealand White rabbits, age 55 days, half male and half female, were randomly assigned to one of four diets in a 2×2×2 factorial arrangement. The diets contained 0% or 0.5% CLA, and 60 or 240mg/kg α-Tocopheryl acetate. Forty-eight rabbits were slaughtered at age 92 days. Growth performances and carcass weight were higher (P<0.05) in 240mg/kg of α-tocopheryl acetate-fed rabbits. Fat and CLA isomers content of Longissimus Lumborum (LL) muscle was higher (P<0.05) in CLA-fed rabbits than control. Fatty acid composition of LL muscle was modified (P<0.05) and oxidative stability was increased (P<0.001) by both dietary treatments. CLA increased (P<0.05) triglyceride, total cholesterol and glucose levels in plasma. Adipocytes in interscapular and perirenal fat in the 240mg/kg α-tocopheryl acetate and 0.5% CLA groups were larger in size but lesser in number than in 60mg/kg α-tocopheryl acetate and no CLA rabbit (P<0.01).

Effect of long term dietary supplementation with plant extract on carcass characteristics meat quality and oxidative stability in pork

The effects of dietary supplementation in pigs with plant extract (PE) from Lippia spp., titrated in verbascoside (5mg/kg feed), from weaning to slaughter (166days), on carcass characteristics, meat quality, collagen characteristics, oxidative stability and sensory attributes of Longissimus dorsi (LD) muscle were examined. Ten pigs per treatment were slaughter at a live weight of 109.5±1.4kg. No influence on carcass characteristics, LD meat quality parameters and collagen characteristics were observed. Dietary PE increased (P<0.001) α-tocopherol levels in LD muscle. Raw LD of pig fed PE showed lower (P<0.001) lipid oxidation levels than controls. A reduction (P=0.05) of fat odor and rancid flavor intensity in cooked LD muscle stored at 4°C for 24h was observed in the treated group. This study shows that PE is an effective antioxidant in pork meat, enhancing oxidative status and sensory attributes, without affecting other meat quality parameters.

Improvement of color and lipid stability of rabbit meat by dietary supplementation with vitamin E

The effects of vitamin E (all-rac-α-tocopheryl acetate) supplementation on meat color and oxidative stability of muscle lipids in New Zealand White rabbits was determined. Twenty animals received pelleted diet (containing 60 mg/kg α-tocopheryl acetate) and 10 of these (treatment group) received drinking water containing 100 mg α-tocopheryl acetate/L for 15 days before slaughter. The α-tocopherol content of the longissimus lumborum muscle (LL) was higher (5.66 vs 1.65 μg/g) in the supplemented group than the control group (p<0.001). The surface redness (a*) of the muscle showed a significant time×treatment effect (p<0.001), decreasing more in the control group over 11 days of storage in the dark at +2.5°C. The lightness (L*) showed a tendency (p=0.06) for a treatment×time effect. No effect of vitamin supplementation was observed on yellowness (b*). Thiobarbituric acid reactive substances (TBARS) in muscle, an index of oxidative stability, were lower in the treated than control group throughout storage (p<0.01 for treatment effect). Vitamin E supplementation appears to be an effective way to improve the color and lipid stability of rabbit meat.

Effect of dietary conjugated linoleic acid (CLA) supplementation on CLA isomers content and fatty acid composition of dry-cured Parma ham

To evaluate the effects of dietary conjugated linoleic acid (CLA) supplementation on cis-9, trans-11 and trans-10, cis-12 isomer content and on the fatty acid composition of subcutaneous adipose tissue and intramuscular lipids of biceps femoris, the lipids of 24 dry cured Parma hams, obtained from Large White pigs fed isoenergetic diets supplemented with either 0 (CON) or 0.25% (T1) CLA from 97 to 172kg live weight, were analysed by Ag(+)-HPLC and capillary GLC. The dietary treatment had no influence on lipid content of BF and subcutaneous adipose tissue but increased (P<0.01) the content of both isomers, more markedly in the latter tissue. CLA supplementation increased (P<0.01) myristic, palmitic, palmitoleic and total saturated fatty acids, and decreased oleic and eicosenoic acids in both tissues. In adipose tissue, an increase (P<0.05) in stearic acid content was observed. Supplementing the finishing diet of heavy pigs with CLA has thus shown to be an effective tool for increasing the CLA content in cured ham and, also, the saturated:unsaturated ratio of the lipids, a positive effect from a technological point of view. From a human nutritional standpoint, the changes occurring in fatty acid composition negatively affect the atherogenic and thrombogenic indexes, but probably these changes are of no particular concern, as they would only partly offset the progressive increase in the degree of unsaturation of heavy pig lipids that has occurred in recent years, as a consequence of reduced adipose depots in carcasses.

Effect of dietary conjugated linoleic acid supplementation in sows on performance and immunoglobulin concentration in piglets

Conjugated linoleic acid isomers may affect the onset and severity of several diseases, including tumors, atherogenesis, and obesity. They may also modulate the immune response. However, little information regarding the most advantageous duration of CLA supplementation is available. The purpose of this study was to determine whether the length of dietary CLA supplementation of a sow affects growth, immune components, and metabolic and hormonal factors in lactating sows and piglets. Gestating sows were fed a control (0%) and a 0.5% CLA-supplemented diet beginning 7 d before parturition and ending 7 d postpartum (T1), or until weaning (T2; 7 sows per treatment). Colostrum and sow and piglet blood samples were collected for the determination of serum metabolite concentrations and immunoglobulin titer. Piglet BW at weaning were greater (P < 0.05) in the CLA groups compared with the control. Dietary CLA supplementation increased (P < 0.05) serum thyroxine concentration in sows, but serum insulin, glucose, NEFA, IGF-I, and leptin concentrations were not affected by CLA supplementation. Colostral IgG, IgA, and IgM titers were greater in sows fed CLA than in control sows (P < 0.05). At weaning (21 d), serum IgG titer of the piglets was greater (P < 0.05) in the T1 and T2 groups than the control group, but at 13 d postweaning, a difference (P < 0.05) was observed between the control and T2 group. The results from this study indicate potential beneficial effects of 0.5% dietary CLA supplementation from 7 d before parturition until 7 d postpartum in improving BW at weaning and immune components in piglets.

Influences of dietary conjugated linoleic acid (CLA) and total lysine content on growth, carcass characteristics and meat quality of heavy pigs

To assess the effects of dietary CLA, lysine and sex on performance, blood metabolites, carcass characteristics, meat quality and skeletal development, seventy-two pigs (initially 105.3±6.6kg live weight) barrows and gilts, were assigned to one of four diets in a 2×2×2 factorial arrangement. The diets contained 0% or 0.75% CLA, and 0% or 0.16% of l-lysine-HCl. All pigs were slaughtered at an average weight of 153.4±11.0kg. Neither CLA nor lysine supplementation influenced growth, blood metabolites or carcass characteristics. CLA reduced (P<0.05) pH(24) and increased (P<0.01) yellowness (b(∗)) of the Longissimus muscle. Lysine increased (P<0.01) pH(24) and reduced (P<0.01) muscle ash content. CLA reduced (P<0.05) collagen synthesis, and lysine increased (P<0.05) collagen synthesis in Longissimus muscle, but no influence on intramuscular collagen maturity or muscle hydroxylysylpyridinoline crosslink concentration were observed. In addition, metacarpal bone diameter was reduced (P<0.05) by CLA. Barrows had higher ADG, final weight (P<0.01), carcass weight, lean percentage (P<0.05), serum cholesterol (P<0.05) and triacylglycerol (P<0.001) than gilts. Metatarsal diameter was larger in gilts than barrows (P<0.05).

Influence of dietary conjugated linoleic acids (CLA) and age at slaughtering on meat quality and intramuscular collagen in rabbits.

To assess the effects of dietary conjugated linoleic acids (CLA) on meat composition and intramuscular collagen (IMC), 144 New Zealand White rabbits, half males half females, 55 days old (1.8 kg LW), were assigned to three weight- and sex- balanced groups and given the following dietary supplements: 0.5% sunflower oil, (C); 0.25% sunflower oil plus 0.25% CLA (T1); and 0.5% CLA (T2). The CLA was prepared from sunflower oil and contained 65% CLA isomers, half cis-9, trans-11 and half trans-10, cis-12. Six males and six females from each group (total 36) were slaughtered at 76, 90 and 104 days of age (corresponding to 2.5, 2.8, and 3.1 kg BW, respectively). The lean fraction was higher and the water content significantly higher in the meat of T2 compared to C and T1 for all ages combined. At the third slaughtering (104 days) the meat fat content was significantly lower in group T2. For all ages combined, IMC content, IMC hydroxylysylpyridinoline (HLP) concentration (index of collagen cross-linking) and IMC maturity (HLP/IMC) were significantly lower in the intermediate supplementation group (T1) compared to C and T2, and were also lower in animals slaughtered at 90 days. CLA supplementation has limited effects on the chemical composition of rabbit meat, with positive effects on meat texture and tenderness after supplementation up to 35 days at 0.25%, and a significant decrease in fat content only at high slaughter weight and high supplementation level (0.5%).

Growth performance and oxidative status in piglets supplemented with verbascoside and teupolioside

Abstract Two hundred forty piglets, half female and half barrows, 8.1 ± 1.40 kg LW, were divided into 6 experimental groups and fed ad libitum with a diet supplemented with the following levels of antioxidants: 0 (CON + = positive control added with 100 mg lincomicine/kg), 5 (LT = low teupolioside or LV = low verbascoside), 10 (HT = high teupolioside; HV = high verbascoside; LT+LV) mg/kg of diet for 56 days. Body weight and feed intake were recorded on d0, 14 and 56 of the trial. Ten piglets from each group were selected and blood collected by anterior vena cava puncture at 0, 14 and 56 d for reactive oxygen metabolite (ROMs) determination. HV showed final weight higher than the other groups (P<0.05), and oxidative stability was improved by both integrations of verbascoside. These results support the view that Verbascoside influences the growth performances and oxidative status of piglets.