• Asian-Australasian Journal of Animal Sciences
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• v.22 no.5
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• pp.681-685
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• 2009

L-carnitine promotes mitochondrial ${\beta}$-oxidation of long chain fatty acids and their subsequent transport across the inner mitochondrial membrane. Although the role of L-carnitine in fatty acid metabolism has been extensively studied, its role in live performance and carcass responses of commercial broilers is less understood. The objective of this research was to determine if Lcarnitine fed at various levels in diets differing in CP and amino acids impacted on live performance and carcass characteristics of commercial broilers. Two floor pen experiments were conducted to assess the effect of dietary L-carnitine in grower diets. In Exp. 1, Ross${\times}$Hubbard Ultra Yield broilers were placed in 48 floor pens (12 birds/pen) and fed common diets to d 14. A two (0 or 50 ppm Lcarnitine) by three (173, 187, and 202 g/kg CP) factorial arrangement of treatments was employed from 15 to 35 d of age (8 replications/treatment). An interaction (p<0.05) in carcass yield indicated that increasing CP (187 g/kg) resulted in improved yield in the presence of L-carnitine. Increasing CP from 173 to 202 g/kg increased (p<0.05) BW gain and decreased (p<0.05) feed conversion and percentage abdominal fat. Feeding dietary L-carnitine increased back-half carcass yield which was attributable to an increase (p<0.05) in thigh, but not drumstick, yield relative to carcass. In Exp. 2, $Ross{\times}Ross$ 708 broilers were fed common diets until 29 d. From 30 to 42 d of age, birds were fed one of seven diets: i) 200 g/kg CP, 0 ppm L-carnitine; ii) 200 g/kg CP, 40 ppm L-carnitine; iii) 180 g/kg CP, 0 ppm L-carnitine; iv) 180 g/kg CP, 10 ppm L-carnitine; v) 180 g/kg CP, 20 ppm L-carnitine; vi) 180 g/kg CP, 30 ppm L-carnitine; and vii) 180 g/kg CP, 40 ppm L-carnitine (6 replications of 12 birds each). BW gain, feed conversion, mortality (30 to 42 d), and carcass traits (42 d) were measured on all birds by pen. There were no treatment differences (p<0.05). However, the addition of 40 ppm L-carnitine in the 200 g CP/kg diet increased (p = 0.06) thigh yields relative to BW in comparison to birds fed diets without L-carnitine, which was further confirmed via a contrast analysis (0 vs. 40 ppm L-carnitine in the 200 and 180 g CP/kg diets; p<0.05). These results indicated that dietary L-carnitine may heighten metabolism in dark meat of commercial broilers resulting in increased relative thigh tissue accretion without compromising breast accretion.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.962-970
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• 2007

A total of 1,200 LinNan Chinese color-feathered chicks were used to study the effects of methionine source [DL-2-hydroxy-4-methylthio-butanoic acid (HMTBa) or DL-methionine (DLM)] and dietary crude protein (CP) level on growth performance, carcass traits, and whole-body nitrogen and fat retention. The trial was designed as a $2{\times}2$ factorial arrangement, including two CP levels (adequate and low) and two methionine sources (HMTBa and DL-methionine). Diets were formulated for three phases, starter (0-21 d), grower (21-42 d), and finisher (42-63 d). Chicks fed HMTBa had higher daily gain and improved feed efficiency than DLM during the grower phase (p<0.05). A significant two-way interaction was observed for growth performance during the finisher phase and overall (0-63 d). Growth performance was greater for chicks fed HMTBa than DLM on adequate-CP diets (p<0.05), but this was not observed at low-CP level (p>0.05). Chicks fed low-CP diets grew slower, used feed less efficiently during the grower, finisher phase and overall. On d 42, regardless of dietary CP levels, birds fed HMTBa had higher carcass weights, breast and thigh weights than DLM-fed birds (p<0.04). Birds fed low-CP diet had lighter carcass weights and less breast muscle, thigh muscle, and dressing percentage at the end of starter, grower and finisher phases (p<0.05). Whole body composition analyses found that birds fed HMTBa tended to contain more protein and less fat compared to those chicks fed DLM at the end of the starter phase (p<0.10). Low-CP diets increased CP concentration in the whole body at the end of the finisher phase (p = 0.05). HMTBa supplementation increased whole-body N retention rate during the finisher phase and overall (p<0.01), and low-CP diets reduced N intake and whole-body fat retention during the finisher phase and overall (p<0.05). In summary, HMTBa was better than DLM on an equimolar basis for growth performance, carcass traits, and N retention in Chinese color-feathered chicks. Low-CP diets lowered growth performance as well as carcass traits in color-feathered birds, probably due to imbalanced AA profiles.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.3
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• pp.351-357
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• 2011

An experiment was conducted to evaluate the effects of castration on growth performance, carcass characteristics, and meat quality of goat kids. Fourteen Boer-cross buck and wether goat kids (n = 7; initial body weight (BW) $38.0{\pm}0.35\;kg$ and $34.8{\pm}0.35\;kg$, for bucks and wethers, respectively) were grazed on annual Marshall ryegrass (Lolium multiflorum Lam.) for 56 days. Body weights were recorded after 4 h withdrawal from feed and water for two consecutive days, every 2 wk. After d 56, animals were harvested and hot carcass weight (HCW), cold carcass weight (CCW), dressing percent (DP), kidney and pelvic fat (KPF), longissimus muscle (LM) area, back fat (BF), and other carcass parameters were measured. Day 0 BW was used as a covariate for analyses. However, bucks were heavier than wethers at d 15 (p = 0.09), 42 (p = 0.001) and 56 (p = 0.001). Bucks had higher ADG (146 vs. 74 g/d; p = 0.001), HCW (21.2 vs. 18.8 kg; p = 0.06) and CCW (20.3 vs. 17.9 kg; p = 0.04) when compared with wether goats. Dressing percentage (51 vs. 47%; p = 0.06), KPF (0.44 vs. 0.16%; p = 0.02) and BF (0.41 vs. 0.21 cm; p = 0.05) were higher in wethers vs bucks, respectively; however, USDA live or carcass grades were similar. Longissimus muscle tissue from wethers and bucks were similar in darkness ($L^*$) and redness ($a^*$), but wethers had more (p = 0.02) yellow tint ($b^*$). Palmitic (C16:0), stearic (C18:0) and oleic (C18:1) acids were higher (p = 0.001) in muscle tissue from wethers compared to bucks. The saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA) contents of muscle tissue were lower (p = 0.001) for bucks with no difference in polyunsaturated fatty acids (PUFA). Longissimus muscle initial temperature was higher in bucks (p<0.04) and pH change post-mortem was similar for bucks and wethers. These results indicated that castration of young market goats reduced growth performance and produced carcasses with more fat and higher SFA.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.8
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• pp.1080-1084
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• 2002

Carcass characteristics of 241 crossbred pigs (Korean wild boars ${\times}$ Landrace sows) were analyzed to examine variations in fasted body weight (FASTWT), carcass weight (CARCWT), dressing percentage (DP), back fat thickness (BFT) and longissimus muscle weight (LMW), and to estimate genetic and phenotypic parameters using three different slaughter-end points. Covariates in the least squares full sib model were slaughter age, fasted body weight and back fat thickness of the carcass. Coefficient of variation was highest for BFT followed by LMW, CARCWT, FASTWT and DP in magnitude. Regressions of three covariates on traits were all linear. However, slaughter age was not significant as a linear covariate for five traits while FASTWT was significant for CARCWT and LMW and BFT was significant for all remaining traits. Genetic and phenotypic variation was considerably reduced by regressing FASTWT or BFT in the model. Heritability estimates of FASTWT, CARCWT, DP and BFT were 0.68, 0.61, 0.11 and 0.49, respectively, using slaughter age as covariate (model 1). Those of CARCWT, DP, BFT and LMW were 0.15, 0.15, 0.30 and 0.11, respectively, using FASTWT as covariate (model 2). Heritability estimates of the traits using LMW as covariate (model 3) were similar to the estimates from Model 1 except that the estimate of CARCWT was reduced to 0.39. Genetic or phenotypic correlations among FASTWT, CARCWT and BFT were all positive and moderate to high. Those between BFT and LMW were also positive and low to moderate. However, genetic and phenotypic correlations between DP and CARCWT were positive while those between DP and FASTWT were negative. It was suggested from this study that differences in carcass yield traits be determined using slaughter age or back fat thickness as slaughter-end point and carcass quality traits using fasted body weight as slaughter-end point.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.10
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• pp.1377-1385
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• 2009

Effect of inclusion of hard vs. soft wheat bran with different particle size on diet digestibility, growth performance and some slaughter traits was evaluated in fattening rabbits. Four isonitrogenous and isocaloric diets were used according to the origin of wheat bran (hard (HWB) - Triticum durum - and soft (SWB) - Triticum aestivum) combined with wheat bran particle size sieved by 2 mm (fine: 2) or by 8 mm (coarse: 8) in a bifactorial (2${\times}$2) study. A growth trial was conducted to measure the effect of treatments on performance in one hundred and twenty New Zealand White${\times}$Californian rabbits fed experimental diets from 50 to 87 days of age. Faecal apparent digestibility was determined within the last week in twenty animals per diet. Digestibility of nutrients was higher (p<0.05) in the diet containing HWB2, except for crude protein, ether extract and ash, than fine and coarse soft wheat bran diets. Final live weight, feed intake and feed consumption of rabbits on the diet with fine hard wheat bran were higher and resulted in greater daily weight gains (p<0.01) than for animals on the other diets. The slaughter yield and percentage value of organs were not significantly (p>0.05) affected by the diets fed; however, the diet containing fine hard wheat bran led to lower (p<0.05) percentages of skin, abdominal fat and carcass drip loss than the other dietary treatments. It is concluded that fine hard wheat bran can be better included in the diet than soft wheat bran to maximize growth performance without affecting carcass traits of fattening rabbits.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.12
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• pp.1718-1734
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• 2009

The aim of this review is to address some characteristics that influence meat quality. Genetic groups, nutrition, finishing systems and gender are the major factors that change carcass characteristics, chemical composition and fatty acid profile. Genetic groups that have zebu genes in their composition show higher hot carcass dressing than genetic groups without zebu genes. Genetic groups that have European breeds in their composition have higher marbling scores. On the other hand, genetic groups that have zebu breeds show low marbling scores. Bulls finished in feedlots present higher final weight than steers, cull cows and heifers. Fat thickness is one of the principal parameters that are affected by different gender. Cull cows (4.72 mm) and heifers (4.00 mm) present higher values than bulls (1.75 mm) and steers (2.81 mm). The major effects observed by different systems of termination are fat thickness and marbling. Crude protein presents variation due to nutrition. Nutrition influences variation of fatty acid profile. Genetic groups also influence fatty acid profile. Genetic groups that have zebu genes in their composition show high percentage of PUFA. The major class of fatty acids that is changed with nutrition is PUFA. The better ratios of PUFA/SFA and n-6/n-3 are found in Longissimus muscle of animals finished in pasture systems.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.5
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• pp.538-544
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• 1998

One hundred and twenty-eight finishing pigs (51.3 kg average initial body weight) were used to determine the effects of adding cellulase enzymes and lactobacillus acidophilus to sorghum-based diets on growth performance, carcass merit, and nutrient digestibility in finishing pigs. Treatments were: 1) corn-soybean meal-based positive control; 2) sorghum-soybean meal-based negative control; 3) Diet 2 with celluloytic enzymes; and 4) Diet 2 with a bacterial feed additive (lactobacillus acidophilus). There was a trend for greater average daily gain (ADG) in pigs fed com versus the sorghum treatments for day 0 to 28 (p < .09), but there was no effect of treatment (p > .15) on overall ADG (i.e., day 0 to 63). Feed consumption was not affected by treatment during the experiment (p > .19). Pigs fed the corn-soybean meal-based diet had 3.5% greater overall gain/feed than pigs fed the other diets (p < .009). Dressing percentage was not affected by treatment (p > .22), but there was a trend for backfat thickness at the last rib to be greater for pigs fed com versus the sorghum treatments (p < .09). Pigs fed the sorghum treatments had 1 % greater fat free lean index (p < .10) compared to pigs fed the corn-soybean meal-based positive control. Pigs fed com had greater apparent digestibilities of DM, N, and GE than pigs fed the sorghum treatments (p < .03), and greater DE intake (p < .07) suggesting that the increased carcass fatness for pigs fed the corn-based control diet resulted from greater energy status of those pigs. In conclusion, pigs fed the corn-soybean meal-based control diet had no improved growth performance but tended to be fatter than pigs fed sorghum. Adding cellulolytic enzymes or a bacterial feed additive to diets for finishing pigs did not affect growth performance, carcass merit, or nutrient utilization.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.2
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• pp.164-169
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• 1997

The present experiment was conducted to evaluate the effects of feed processing and feeding methods on growth performance and carcass characteristics of growing-finishing pigs. A total of 72 pigs (LYD, 22.24 kg BW) were employed for a 90-d feeding trial. Treatments were 1) mash dry feeding (MD), 2) mash wet feeding (MW), 3) pellet dry feeding (PD), and 4) extruded pellet dry feeding (EPD). Corn, soybean meal and wheat bran in the basal diets were extruded before mixing and pelleting for EPD diet production. Ileal or fecal digestibility and carcass traits including lean meat percentage and weights of stomach ulcer were also examined. During the growing period, pigs fed PD showed improved (p < 0.05) average daily gain (ADG) and feed conversion (F/G) over those fed MD, whereas no significant differences in average daily feed intake (ADFI) were found among dietary treatments. Finisher pigs fed MD showed lover, but not significant, ADG and F/G than those fed MW, PD or EPD. For the overall period, pigs fed PD grew faster (p < 0.05) than those fed MD or EPD. Feed intake was different between the two feeding methods (MD vs MW), and between the two processed feeds (PD vs EPD). The digestibility of crude fat was higher (p < 0.05) in pigs fed EPD than in pigs fed mash feeds. NFE digestibility of EPD treatment was also higher (p < 0.05) than that of PD. Back fat (10th rib area) was thicker (p < 0.05) tn pigs fed MD than in pigs fed EPD. other carcass traits including incidence of esophagogastric ulcers were not different among treatments. In conclusion, pelleting appeared to bo the desirable processing methods and wet feeding could also be recommended for growing-finishing pigs.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.5
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• pp.712-720
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• 2018

Objective: The aim of this experiment was to evaluate the effect of dietary supplementation with the docosahexaenoic acid (DHA)-rich microalgae, Aurantiochytrium limacinum (AURA) on pig performance, carcass traits, and the fatty acid composition of pork Longissimus lumborum (LL) and backfat. Methods: A total of 144 Pig Improvement Company (PIC)${\times}$Goland finishing pigs (72 females and 72 castrated males) of mean weight 117.1 (${\pm}13.1$) kg were blocked by sex and body weight and provided with 0% or 1% AURA in isonutritive and isocaloric diets. A total of 24 pens provided 12 replicates per treatment. Animals were weighed on day 0 and 28 with feed and water intake recorded per pen. After 31 days supplementation (28 days of study and 3 days until the slaughtering date) three animals per pen (n = 72) were slaughtered and the LL and backfat thickness, lean meat content and dressing percentage were recorded for the carcasses. The fatty acid (FA) profile of the LL and backfat was established by direct FA methyl ester synthesis. Results: No differences were observed for any performance parameters or carcass traits. Supplementation with AURA resulted in significant changes to the FA profiles of both the LL and backfat with male and female pigs responding differently to supplementation in terms of particular FAs. Overall, pork LL samples had significantly higher eicosapentaenoic acid (p<0.001) and DHA concentrations (p<0.001), and higher omega-3 (n-3) FAs (p<0.001), as well as an increased omega3:omega6 (n-3:n-6) ratio (p = 0.001). For backfat, supplementation resulted in significantly higher amounts of DHA (p<0.001) and n-3 FAs (p<0.001). Conclusion: These results indicate that dietary supplementation with 1% AURA over a 31 day period can increase the FA composition of pork LL and backfat, specifically the DHA, with no major impact on growth performance and carcass traits.

• Asian-Australasian Journal of Animal Sciences
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• v.23 no.4
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• pp.475-482
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• 2010

Thirty-six Najdi ram lambs, weighing an average of 24 kg and circa 3 months old, were utilized in this trial to evaluate the effects of various alfalfa hay particle lengths in the diet on growth performance, digestion coefficients, nitrogen retention and carcass characteristics. Lambs were randomly allotted to three dietary treatments: 9.5 and 14 mm diets, where alfalfa hay was processed to 9.5 and 14 mm particle lengths, respectively, mixed with 3 parts of concentrate and pelleted as a total mixed ration (TMR), and long hay diet, where one part of loose alfalfa hay (17.8${\pm}$2.4 cm) was offered in combination with 3 parts of only-concentrate pellet. All dietary treatments were homogeneous in their ingredient composition. All lambs were slaughtered after a 14-week feeding trial. Although the results showed no significant effect of hay particle length on DMI, TDN and DCP, lambs fed the 9.5 mm pelleted diet had higher (p<0.05) final body weight, ADG, gain efficiency and nitrogen retention than lambs fed the 14 mm and long hay diets. Altering the particle length of alfalfa hay in diets did not affect the digestibility of DM or CP, whereas digestibilities of ADF and NDF were 3.7% and 5.4% higher (p<0.05), respectively, for the long hay diet versus the 9.5 mm pelleted diet. Hot carcass weight, percentage of separable lean from the $9-11^{th}$ rib joint, and percentages of protein and EE in the separable lean increased (p<0.05) as the particle length of alfalfa hay in the diet decreased. Under the conditions of this study, the reduction of particle length in the TMR played an important role in enhancing performance without altering DM consumption, and this may lead to more efficient productivity of lamb fattening compared with longer chopping lengths.