A. Manchisi

Effect of age on fatty acid composition of Italian Merino suckling lambs.

The present study was undertaken to evaluate the effect of age on lipid content and composition of lamb meat. Thirty suckling ram lambs of the Italian Merino breed, reared according to a traditional semi-extensive management, were slaughtered at 30, 50 and 70 days of age to evaluate total lipids and fatty acid profile in three different muscles: longissimus dorsi (LD), semimembranosus (SM) and quadriceps femoris (QF). Age did not dramatically modify lipid content and composition, even if effects of nutritional interest were observed. Meat from lambs slaughtered at 70 days of age presented the best fatty acid profile, because they had the highest PUFA content and ratio to SFA, as well as the lowest thrombogenic index. The SM muscle had better nutritional quality than the LD and the QF, as a result of a higher PUFA percentage and PUFA/SFA ratio, together with a lower thrombogenic index. These characteristics were also associated with slightly lower amounts of intramuscular lipids and SFA.

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%).

The effect of dietary energy and vitamin E administration on performance and intramuscular collagen properties of lambs.

The effect of different dietary energy levels, with or without injections of vitamin E, on growth, carcass traits and intramuscular collagen (IMC) characteristics of growing lambs was studied. Twenty-four Ile de France ram lambs were evaluated in a 2×2 factorial design involving different DL-α-tocopheryl acetate injections (C, control=0 and V=150IU/wk, i.m. for eight wk) and energy level (N, normal=7.61 and L, low=6.47MJ/kg DM). Growth and slaughter performance, and IMC characteristics were not influenced by diet. DL-α-tocopheryl acetate increased ADG during suckling, while it did not affect live weight, carcass weight and dressing percentage. Vitamin E injections reduced carcass shrinkage but also had a negative effect on pelvic limb percentage. The Longissimus muscle pH values were higher in V than in C lambs. DL-α-tocopheryl acetate reduced IMC maturity and muscle hydroxylysylpyridinoline crosslink concentration, more markedly in lambs fed low energy diets.

Effect of suckling management on productive performance, carcass traits and meat quality of Comisana lambs.

The effect of restricted suckling on productive performance, carcass traits, meat quality and skeletal development of growing lambs was studied. Twenty-one naturally suckled male Comisana lambs were divided into three equal weight groups differing in suckling management systems: (1) only maternal milk (C); (2) only maternal milk until 15th day of age, and then, till slaughter, maternal milk, concentrate and Lucerne hay ad libitum (T1); (3) only maternal milk until 15th day of age, and then from 16th to 30th days of age, maternal milk, concentrate and Lucerne hay ad libitum, and, from 31st day of age till slaughter, only concentrate and Lucerne hay ad libitum (T2). The total mean milk yield was 22.7 and 41.6kg per ewe for T1 and T2, respectively. Restricted suckling did not significantly affect slaughter weight, hot and cold carcass weights, carcass shrink losses, pH, colour and area of Longissimus muscle, pelvic limb, or bone characteristics. Suckling management system significantly affected ADG, milk intake, dressing percentage, and percentages of intestine, stomach, offal, kidney fat, shoulder, lean and fat, and there were differences in total collagen, and hydroxylysylpyridinoline crosslink concentrations. In addition, different IMC maturity among the muscles was apparent.

Cryopreservation of turkey semen by the pellet method: effects of variables such as the extender, cryoprotectant concentration, cooling time and warming temperature on sperm quality determined through principal components analysis.

This study was designed to identify the best pellet cryopreservation procedure for the cryosurvival of turkey semen among 192 different treatments established by variations and permutations of seven conditions used in the freezing/thawing process. These conditions were: diluent (IGGKPh, SPh or Tselutin); dilution rate (1:3 vs. 1:4); cooling time (45 vs. 60 min); dimethylacetamide (DMA) concentration as cryoprotectant (6 vs. 8%); equilibration time in DMA (1 vs. 5 min); semen drop volume (50 vs. 80 μL) and thawing temperature (60 vs. 75 °C). Through principal components analysis (PCA), post-thaw sperm quality data (mobility, viability and membrane functional integrity) were reduced to a single output variable (Sperm Quality) indicating overall post-thaw semen quality. All treatments induced a significant reduction in semen quality after warming (P < 0.01), though one set of seven conditions, or treatment, was identified by PCA to generate the highest Sperm Quality score and a further five treatments yielded a score not significantly different (P > 0.05) from this best score. Although still not fulfilling the requirements for commercial application, our findings serve to identify the critical steps in turkey sperm cryopreservation that need to be assessed in future studies.

Effects of slaughter weight and sex on carcass traits and meat quality of Casertana pigs reared outdoors

Abstract The effects of different slaughter weights (W) and sex (S) on carcass traits and longissimus dorsi meat quality (pH, WHC, colour, cholesterol and collagen) of Casertana pigs were studied. Thirty-six pure breed Casertana pigs, 24 barrows (B) and 12 gilts (G), were evaluated in a 2x2 factorial design involving different slaughter live weights (L, 125.6 kg; H, 152.5 kg) and S (B and G). H pigs had higher carcass weight (P<0.01), dressing percentage (P<0.05), ham yield (+ 7.9 %; P<0.01), lean meat cuts (P<0.01) and backfat thickness (+13.3%; P<0.05), and lower (P<0.01) loin yield and fatty cuts. W did not affect pH and WHC. L pigs produced lighter (P<0.01) and more yellow meat (P<0.01), while H pigs showed lower (P<0.01) hue value. Cholesterol content resulted higher (P<0.05) in H pig meat. Collagen properties were affected by W. Compared to G, B had higher dressing percentage (P<0.05) and backfat thickness (P<0.01), smaller loin area (P<0.01), slightly lower (P<0.08) loin yield and less (P<0.01) lean cuts. S did not affect any meat quality traits.

Cryopreservation of rabbit semen using non-permeable cryoprotectants: Effectiveness of different concentrations of low-density lipoproteins (LDL) from egg yolk versus egg yolk or sucrose

This study was designed to identify the most effective non-permeable cryoprotectant (CPA) for the cryopreservation of rabbit semen by comparing the effects of different concentrations of low-density lipoproteins (LDL) on post-thaw sperm quality with those of whole egg yolk or sucrose. In a second experiment, the performance of the non-permeable CPAs identified as most effective was assessed in vivo by determining reproductive performances. Pooled semen samples were diluted to a ratio of 1:1 (v:v) in freezing extender (Tris-citrate-glucose and 16% dimethylsulfoxide as permeable CPA) containing as non-permeable CPAs 6, 8, 10 or 15% LDL from egg yolk, 0.1M sucrose, or 15% egg yolk. The semen was loaded in 0.25mL straws and frozen in liquid nitrogen vapor. After thawing, we determined sperm motility, viability, osmotic resistance, and acrosome and DNA integrity. Our results clearly revealed a significant effect of LDL concentration on semen quality. Also, at an optimal concentration of 10%, motility and acrosome integrity were improved over the values recorded for egg yolk (P<0.05). Based on the in vitro data, 3 groups of does (n=30 each) were inseminated with fresh semen or semen frozen using sucrose or 10% LDL. Sucrose led to a significantly higher conception rate than LDL and reproductive performance was similar to that observed for fresh semen. Our findings indicate the markedly better performance of sucrose in vivo as a non-permeable CPA for the cryopreservation of rabbit semen.

Superovulation and embryo production in ewes using a commercial p-FSH

The effectiveness of a commercial porcine pituitary extract (p-FSH) with a 1:1 FSH/LH ratio was assessed on ovarian response and embryo yield in ewes. During the breeding season, 60 Altamurana ewes were synchronized with FGA-impregnated intravaginal sponges and subdivided into four treatment groups (n = 15). Beginning 24 h before sponge removal, ewes were treated with 250 (Group 1), 500 (Group 2), 750 (Group 3) or 1000 IU p-FSH (Group 4) administered in a series of four decreasing doses over a period of 36 h. The ewes were monitored for estrus every 4 h, with ovarian response and embryos evaluated on the seventh day following sponge removal. No differences were found among the treatments in incidence of estrus and ovulation. Although treatment with 250 IU p-FSH produced the fewest ovulations, animals in this group yielded a higher (P < 0.01) number of viable embryos, a lower (P < 0.01) number of unfertilized ova, and a lower (P < 0.05) incidence of unovulated follicles and abnormal corpora lutea when compared with animals treated with 750 or 1000 IU p-FSH, while treatment with 500 IU p-FSH yielded intermediate results. It is concluded that the commercial porcine pituitary extract (Pluset) at moderate doses (250 IU) is suitable for superovulation in ewes as it induces a high ovulatory response and transferable embryo yield.

Cryopreserving turkey semen in straws and nitrogen vapour using DMSO or DMA: effects of cryoprotectant concentration, freezing rate and thawing rate on post-thaw semen quality

Abstract 1. This study was designed to identify a suitable protocol for freezing turkey semen in straws exposed to nitrogen vapour by examining the effects of dimethylacetamide (DMA) or dimethylsulfoxide (DMSO) as cryoprotectant (CPA), CPA concentration, freezing rate and thawing rate on in vitro post-thaw semen quality. 2. Pooled semen samples were diluted 1:1 (v:v) with a freezing extender composed of Tselutin diluent containing DMA or DMSO to give final concentrations of 8% or 18% DMA and 4% or 10% DMSO. The semen was packaged in 0.25 ml plastic straws and frozen at different heights above the liquid nitrogen (LN2) surface (1, 5 and 10 cm) for 10 min. Semen samples were thawed at 4°C for 5 min or at 50°C for 10 s. After thawing, sperm motility, viability and osmotic tolerance were determined. 3. Cryosurvival of turkey sperm was affected by DMSO concentration. Freezing rate affected the motility of sperm cryopreserved using both CPAs, while thawing rates showed an effect on the motility of sperm cryopreserved using DMA and on the viability of sperm cryopreserved using DMSO. Significant interactions between freezing rate × thawing rate on sperm viability in the DMA protocol were found. 4. The most effective freezing protocol was the use of 18% DMA or 10% DMSO with freezing 10 cm above the LN2 surface and a thawing temperature of 50°C. An efficient protocol for turkey semen would improve prospects for sperm cryobanks and the commercial use of frozen turkey semen.