Effect of coconut processing by-product graded feeding on carcass traits and meat quality of lambs.

The inclusion of by-product coconut mesocarp skins (CMS) in diets was evaluated in feedlot lambs. The objective of this study was to evaluate CMS levels effects on carcass traits and meat quality of lambs. Thirty-five male lambs with an initial body weight of 16.9 ± 2.93 kg were distributed in a completely randomized design with five CMS levels in total dry matter (0; 4.8; 9.6; 14.4 and 19.2%) and fed during 71 d until slaughter. High levels of CMS decreased the intake of dry matter and negatively affected the performance of lambs. Fat and protein contents of Longissimus lumborum muscle (P < 0.05) and the saturated fatty acid (FA) decreased (P < 0.001) whereas polyunsaturated FA increased (P < 0.01) with the inclusion of CMS. The ratio t10/t11-18:1 increased with the inclusion of CMS (P < 0.001). The instrumental color descriptors were unaffected by CMS levels. According to the effects on the investigated meat quality traits we recommend up to 4.8% CMS in diets of confined lambs.

Fatty acid composition of polar and neutral meat lipids of goats browsing in native pasture of Brazilian Semiarid.

Thirty six male goats grazing Caatinga native pasture were randomly assigned to 4 concentrate supplementation levels (0, 5, 10 and 15g/kg of body weight) and slaughtered after 120days. Longissimus muscle meat lipids were extracted and fractionated into neutral (NL) and polar (PL) lipids. Supplementation of grazing goats increased linearly (P<0.05) intramuscular fat (1 to 1.5% of meat) and NL (0.3 to 1% of meat) but decreased linearly (P=0.044) the PL (0.66 to 0.50% of meat). On NL, supplementation increased linearly (P=0.047) the proportion of c9-18:1 (31 to 40% of FA) with supplementation. On PL, supplementation reduced linearly (P<0.03) the dimethyl acetals, 18:3n-3 and most of long chain polyunsaturated FA (PUFA) proportions but increased linearly (P<0.001) the c9-18:1. Considering the total meat FA, supplementation led to an increase of the saturated and monounsaturated FA contents and a decrease of the long chain n-6 and n-3 PUFA contents.

Biochemical and hormonal parameters of lambs using guava (Psidium guajava L.) agro-industrial waste in the diet.

The objective of this research was to evaluate the biochemical and hormonal parameters of Santa Inês sheep that received diets with different levels of guava agro-industrial waste (GAW). Forty non-castrated male animals of the Santa Inês breed were used, with an average initial weight of 21.3 ± 2.6 kg, and an average age of 120 days. The animals were distributed in a completely randomized design, with five treatments and eight replicates, and fed with increasing GAW levels replacing hay (0.0, 7.5, 15.0, 22.5 and 30.0%). After the beginning of the diet period, blood samples were collected every 2 weeks approximately 3 h after feeding. Cholesterol concentration had a significant effect (P < 0.01) with the inclusion of GAW. The animals that ingested the control diet had the highest concentrations of cholesterol. T3 and T4 hormones showed a significant difference (P < 0.01) among the treatments, i.e. the animals that ingested the control diet had the lowest concentrations of these hormones. We concluded that the inclusion of GAW in up to 30% decreases the concentration of cholesterol and increases the concentrations of T3 and T4 in the blood, aiding the metabolism of the animals.

New insights on the metabolism of ricinoleic acid in ruminants.

Dairy goats were fed a total mixed ration with or without the inclusion of castor oil [40 g/kg of dry matter (DM)] to study the metabolism of ricinoleic acid (12-OH,cis-9-18:1). Ten goats, at 39.7 ± 4.0 d in milk, were individually penned and allocated at random to the 2 experimental diets. Goats were manually milked twice a day. Milk fatty acids (FA) were analyzed as methyl esters and hydroxyl groups were derivatized in trimethylsilyl ethers. Apart from ricinoleic acid, 6 FA were only detected in the milk of the castor oil group. Ricinoleic acid composed 0.3% of total FA in milk of the castor oil group, whereas the hydroxy-FA (8-OH-14:0, 10-OH-16:0, and 12-OH-18:0) and oxo-FA (8-oxo-14:0, 10-oxo-16:0, and 12-oxo-18:0) reached 7.5% of total FA in milk. We anticipate that these FA were derived from the metabolism of ricinoleic acid, although it was not clear if they were produced in the rumen or in the tissues. To confirm that, we conducted in vitro batch incubations repeated for 3 consecutive weeks with castor oil (40 g/kg of DM) and strained rumen fluid from 2 fistulated sheep. To examine the products formed over time, incubation tubes were stopped at 0, 6, 12, 24, 48, and 72 h. The results of the in vitro experiment showed that ricinoleic acid was metabolized in the rumen at a slow rate and the main products formed were 12-OH-18:0 and 12-oxo-18:0, by hydrogenation of the cis-9 double bond, followed by oxidation of the hydroxyl group, respectively. Our results suggest that the 12-OH-18:0 and 12-oxo-18:0 escape rumen and are further metabolized through partial ß-oxidation in ruminant tissues. We propose that the 10-OH-16:0 and 8-OH-14:0 found in goat milk of the castor oil group are successive products of the ß-oxidation of 12-OH-18:0, and the 10-oxo-16:0 and 8-oxo-14:0 are successive products of the 12-oxo-18:0 in tissues. Overall, our results indicate that ricinoleic acid is extensively metabolized in the rumen and tissues, producing mainly oxo- and hydroxy-FA that are further excreted in milk.