Effect of an outdoor rearing system on the welfare, growth performance, carcass and meat quality of a slow-growing rabbit population

The effect of Outdoor or Indoor housing systems on the growth, welfare and carcass and meat quality of a local rabbit population was investigated. The slaughter age was 103 ± 2 days. Open-field tests showed an effective capacity of the Outdoor group to combat stressors. Compared to Indoor rabbits, Outdoor rabbits showed better growth performance and higher slaughter weight (SW) (2535 vs 2137 g; P < 0.01). Outdoor housing conditions increased the physical activity of rabbits and their hind legs were more developed (36.1% vs 34.9%; P < 0.01). Slaughter yield was lower in Outdoor rabbits (57.8% vs 58.4% SW; P < 0.05) due to the higher skin proportion (17.2% vs 15.6% SW; P < 0.05). Outdoor rabbit meat showed lower L* value (L. lumborum: 55.6 vs 59.2; P < 0.01; B. femoris: 53.0 vs 55.5; P < 0.01) and cooking loss (L. lumborum: 15.9% vs 18.1%; P < 0.05). Outdoor rabbit hind leg meat was characterized by lower water (74.5% vs 75.1%; P < 0.01) and higher protein (22.9% vs 22.6%; P < 0.01) and fat (1.4% vs 1.1%; P < 0.01) contents; lipids were lower in SFA and higher in MUFA. Outdoor rearing seems to be a possible alternative housing system that allays the ethical concerns of modern consumers while also providing good meat quality.     

The effect of journey time and stocking density during transport on carcass and meat quality in rabbits

Four hundred and fifty hybrid commercial rabbits (half males and half females) at the end of their productive cycle (82 days old) were transported in cages (98 × 52 × 24 cm, length × width × height) at high or low density (75.5 or 49.0 kg/m² – 15 or 10 animals per cage) on an uncovered truck for 1, 2 or 4 h. Live weight before and after transport as well as slaughter data were recorded for each rabbit. A subset of 180 carcasses were evaluated for meat quality on the basis of meat pH, colour (CIELab system), cooking loss, drip loss and shear force. As a representative of the whole carcass muscle/bone ratio, the left hind leg was separated, dissected and its meat analysed in order to determine its water, protein, ash and lipid content. It was found that a longer journey significantly increases the live weight losses (3.3% vs. 2.0% vs. 1.6% for 4, 2 or 1 h, respectively; P < 0.001), as a result not only of urine and fecal losses, but also of a decrease in carcass weight (P < 0.01) during transport. Ultimate pH (pH_u) was higher and pH drop lower in rabbits transported for 4 h compared to those transported for 2 h (P < 0.05). Moreover, the meat from animals that had undergone the longest journey was more purple-red (P < 0.05), darker (P < 0.0001), and firmer when raw and showed less cooking loss than meat from those that underwent shorter journeys. Transport density did not influence any of the considered parameters and there was no interaction between transport time and density.     

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 41.6 kg 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.     

Changes in carcass composition and meat quality when selecting rabbits for growth rate

Sixty rabbits from the 23rd generation (group S) of a line selected for growth rate were compared to sixty rabbits from the 7th generation of the same line (group C) to study possible relevant changes in carcass composition and meat quality due to the selection and the consequent decrease in degree of maturity at slaughter weight (2000 g). The only relevant changes in carcass composition were an increase in kidneys, liver and dissectible fat percentages and a decrease in meat to bone ratio of the hind leg. In m. Longissimus, group S had lower yellowness of the carcass and higher redness and yellowness of the meat. ICDH activity increased and the aldolase:ICDH ratio decreased. In the hind leg, group S had higher values of PUFA, PUFA/SFA ratio and n − 3 fatty acids.     

Effect of housing conditions on production,carcass and meat quality traits of growing rabbits

Production, carcass traits and meat quality of rabbits housed in cages or in different pens were compared. Rabbits (n = 579) were sorted into 5 groups: C = cage (2 rabbits/cage); pen without platform: P11 = 9 rabbits/pen; P16 = 14 rabbits/pen; pen with platform: PW = wire net platform, 14 rabbits/pen; PD = platform with straw-litter, 14 rabbits/pen. Feed intake and average daily gain between 5 and 11 weeks, and body weight at 11 weeks were significantly higher in C rabbits than that of the mean of pen-housed groups, while the PD group had the lowest growth performance. C rabbits had the smallest hind part to reference carcass (P < 0.001) and the largest percentage of perirenal and scapular fat (P < 0.001). The meat/bone ratio was the largest in group C (P < 0.05). Differences were recorded in a* value and lipid content of m. Longissimus dorsi. Rabbits housed in cages generally had the best performance whereas those housed in pens with platform exhibited the worst.     

The effect of selection for growth rate on carcass composition and meat characteristics of rabbits

The effect of selection for growth rate on carcass composition and meat quality was assessed by comparing two groups of rabbits belonging to different generations of a selection experiment. A Bayesian approach was used. Embryos belonging to generations 3 and 4 of selection were frozen and thawed to be contemporary of animals from generation 10. A control group (C), formed from offspring of these embryos, was contemporary to offspring of generations 10 and 11 of selection, chosen at random, which constituted the selected group (S). One hundred and thirty-one contemporary rabbits were slaughtered at approximately the Spanish commercial live weight of 2 kg. Carcasses were dissected and measured according to the norms of the World Rabbit Scientific Association. An animal model including effects of genetic group (C, S) and sex, and slaughter weight as a covariate was used. S animals had a higher development of liver, kidneys and of a set of organs consisting of the thymus, trachea, oesophagus, lung and heart, relative to C. For dissectible fat, S animals had less than C: −0.31 g for scapular fat, −1.62 g for perirenal fat and −2.03 g for inguinal fat. S had a lower content (−0.39%) of dissectible fat percentage in the “Reference” carcass, indicating a lower degree of maturity at slaughter. The meat to bone ratio was not affected by selection, but the meat and bone contents of the hind leg were 3.25 and 0.71 g higher, respectively, in the C group. Selected animals had a lower water holding capacity in the raw meat (−2.10%), a higher water holding capacity in the cooked meat (2.17%), a higher cooking loss (3.31%) and a lower fat percentage in the meat of a hind leg (−0.37%). Females had more fat than males: 0.26 g for scapular fat, 1.02 g for perirenal fat, 1.10 g for inguinal fat, and 0.24% for total dissectible fat percentage of the “Reference” carcass.     

The influence of fiber size distribution of type IIB on carcass traits and meat quality in pigs

The effects of detailed characteristics such as the size and proportion of type IIB fibers in longissimus thoracis muscle on carcass traits and pork quality were investigated. A total of 96 pigs were classified into four groups by the proportion of different IIB fiber sizes. Group NS (high proportion of both small- and normal-sized IIB fibers) had a higher total number (136.4) and density (231.31) of type IIB fibers, backfat thickness (37.20 mm) and intramuscular fat content (4.77%) than the other groups (P < 0.05), whereas Group NS had the lowest values of cross-sectional area (3413.85 μm²) and diameter (60.15 μm) of type IIB fiber among the groups (P < 0.05). Pig muscles with higher percentage of large IIB fibers exhibit tougher, lighter and more exudative meat than pig muscles with a higher proportion of small- or normal-sized IIB fibers. Therefore, an increase in the proportion of large IIB fibers causes poor quality of pork.     

Effects of metabolic modifiers on carcass traits and meat quality

Much research has been conducted and published about metabolic modifiers that increase growth rate, improve feed efficiency, increase carcass leanness, and decrease carcass fatness. Most of these metabolic modifiers have been developed to improve efficiency and profitability of livestock production and to improve carcass composition, with fewer of them developed and researched specifically to improve meat quality. Some of the metabolic modifiers can have negative effects on visual and sensory meat quality, especially when not used as recommended. This review evaluates the various kinds of metabolic modifiers that have been researched for their effects on production efficiency, carcass composition, and meat quality. Nutritional composition of meat generally is improved from use of most of the metabolic modifiers, visual quality is improved by others, but some can have a negative effect on marbling and tenderness. Anabolic steroid implants are very cost effective and practical for beef cattle production but aggressive implants used within 70 days of slaughter or too frequent use of them will reduce tenderness and marbling. Somatatropin and approved β-agonists are very effective in improving growth performance and carcass leanness in pigs, and β-agonists are effective in cattle, but improper use of them can have negative effects on marbling and tenderness. Feeding supplemental levels of vitamin E is quite beneficial for improving meat color and shelf-life of beef, lamb, and pork, whereas not supplementing diets with vitamin A has potential for improving marbling in cattle. Immunocastration shows promise for capitalizing on the efficiency of muscle growth of young boars up to a few weeks before slaughter, at which time boar taint is prevented and marbling is improved by immunocastration. Potential exists for improving the fatty acid profile of lipids and increasing conjugated linoleic acid content in beef through dietary manipulation. Supplementing swine diets with conjugated linoleic acid can improve carcass composition of swine, but is not yet cost effective to use. Dietary inclusion of magnesium, manganese, or chromium in diets of pigs and sheep has potential to improve meat color and water-holding capacity. Although, not all of these metabolic modifiers are approved in all countries, proper use of the ones that are approved offers opportunities for economically improving production efficiency and carcass leanness while maintaining acceptable marbling and tenderness, while some provide opportunities to enhance meat color and quality.     

Effects of tomato pomace supplementation on carcass characteristics and meat quality of fattening rabbits

The aim of this study was to determine how a feeding plan characterized by different levels of tomato pomace (TP) supplementation influences the carcass characteristics, the chemical, physical and sensorial characteristics of rabbit meat. 144 weaned crossbred rabbits were divided into three groups of 48 each. The first group was fed a basal diet without TP, while the other two groups were fed the basal diet after replacing part of the diet with TP at 3% and 6%, respectively. There was a significant difference between the experimental groups in terms of live and carcass weights. The meat of rabbits fed on a 6% TP diet exhibited higher yellowness (b*) and Chroma values when compared to others. The saturated fatty acid content in the longissimus dorsi muscle and perirenal fat decreased significantly with increasing TP inclusion, while polyunsaturated fatty acids increased. Furthermore, our results indicate that a diet integrated with 6% TP could influence positively the overall preference of cooked meat.     

Comparison of carcass and meat characteristics of three rabbit lines selected for litter size or growth rate

Rabbits from three synthetic lines were compared. Line V and A were selected for litter size at weaning and line R was selected for growth rate between weaning and slaughter time. Forty animals of each line were slaughtered at 9 week of age. Comparisons between lines were made using Bayesian statistical techniques. Line R had a higher meat/bone ratio, higher loin percentage and higher ultimate pH of M. Longissimus lumborum (LL) than A and V, but lower dressing out and lower hind part percentages. Some differences between lines in carcass and meat colour were found. No differences were found for percentage of released water of LL and for the activity of energy metabolic enzymes. At present, rabbit carcasses are not costed according to their retail cuts or meat/bone ratio, but dressing out percentage is taken into account, thus breeding companies should be concerned about lower carcass yield of lines selected by growth rate.     

Effect of forage to concentrate ratio on growth performance, and on carcass and meat quality of Podolian young bulls

The effect of forage to concentrate ratio: 60-40 [high concentrate group (HC) and 70-30 [low concentrate group (LC)] on growth, slaughtering performance and meat quality were evaluated in twenty organically farmed Podolian young bulls. Meat quality characteristics were measured on three different muscles [Longissimus dorsi (LD), Semimembranosus (SM) Semitendinosus (ST)], vacuum-packaged and chilled stored at 2-4°C for 15 days. The animals in the HC group had higher weight gain than those in the LC group (P<0.05). Slaughter data were not influenced by ration composition. The higher forage to concentrate ratio produced an improvement in fatty acid composition of the three muscles, with a higher polyunsaturated to saturated ratio (P<0.001). Vitamin E and malondialdehyde (MDA) contents were not affected by the feeding treatment. Panel scores for tenderness and flavour (P<0.01) and Warner-Bratzler Shear force (P<0.001) were significantly affected by muscle, the LD muscle being the most tender and the richest in flavour but they not affected by dietary treatment.     

Effect of the insulin-like growth factor-II and RYR1 genotype in pigs on carcass and meat quality traits

Recently, a new QTN (quantitative trait nucleotide), which is located in the regulatory sequence of the imprinted IGF-II gene was discovered in the pig and is associated with a significant increase in IGF-II mRNA expression in skeletal muscle during postnatal growth. The aim of the current study was to investigate the effect of the IGF-II paternal allele (Apat and Gpat animals that inherited, respectively, the mutant and wild type paternal allele of interest) on carcass and meat quality traits in Nn and NN RYR1 genotypes. A total of 141 animals were measured, almost equally distributed over the IGF-II and RYR1 genotypes and gender. The Apat allele increased carcass lean meat percentage with approximately 4.5% (P < 0.001) as a result of decreased backfat thickness. Average live weight daily gain was not affected, hence average daily lean meat gain was significantly higher for Apat compared to Gpat animals. The IGF-II mutation had no noticeable effect on meat quality in contrast with the RYR1 mutation. No interaction effects of both mutations on meat quality were noticed.     

Effect of concentrate level and slaughter body weight on growth performances,carcass traits and meat quality of Barbarine lambs fed oat hay based diet

This study was conducted to evaluate concentrate level (CL) and slaughter body weight (SW) effects on growth performances, carcass traits and meat quality of Barbarine lambs. Twenty-four weaned male lambs (23.1 kg), receiving an oat-hay based diet, were allotted into two groups. The LCL group received low concentrate level (300 g) and the HCL group received high concentrate level (600 g). Lambs were slaughtered at two prefixed weights (35 and 42 kg). For each group and each weight, six lambs were slaughtered. Lambs from HCL group had higher ADG, carcass yields, carcass compactness and subcutaneous fat thickness, and lower carcass meat proportion. CL increase did not affect meat pH, meat and fat color, chemical and fatty acid composition. Late slaughtering improved carcass yields and increased carcass adiposity. However, it did not affect carcass meat proportion and shoulder tissue composition. SW had effect on meat color and fatty acid composition.     

Effects on growth performance, carcass characteristics, and the fat and meat fatty acid profile of rabbits fed diets with chia (Salvia hispanica L.) seed supplements

The effects of three levels (0%, 10%, or 15%) of chia (Salvia hispanica L.) seed (SHS) included in the diet on the growth performance, some carcass characteristics and fatty acid profile of rabbit meat and perirenal fat was studied. At the end of the experiment, there were no significant differences among the groups in live weight, live weight gain, feed consumption, feed efficiency, carcass yield or the percentages of edible organs. The percentage values of hind legs, fore legs, loin and abdominal wall, breast and ribs, skin and limbs, and head were not affected by the inclusion level of SHS. The polyunsaturated fatty acid (PUFA) concentration in the longissimus dorsi muscle and perirenal fat was significantly increased with increasing SHS inclusion, while the saturated fatty acid (SFA) decreased. The n − 6/n − 3 PUFA ratio of the rabbit meat decreased from 4.55 in the control group, to 1.03 in the 15% SHS group.     

Effects of slaughter weight on carcass composition and meat quality in pigs of two different growth rates

Three hundred and forty (340) Duroc×(Landrace×Yorkshire) crossbred piglets were allotted to a 2×2×3 factorial design experiment. The independent variables were the growth rate (fast: around -10 days at 100kg and slow: around +2 days at 100kg), based on two different EBV's (estimated breeding value) of the sire-line for age, the sex (barrows and gilts) and the live weight at slaughter (107, 115 and 125kg). A sub-population of 119 pigs (10 carcasses per treatment) was selected for the carcass and meat quality evaluation trials. As live weight increased there were significant increases in hot carcass weight and dressing percentage (P<0.05). Lean, fat and bone proportions were not affected by weight. Gilts had higher lean proportion (P<0.05) than barrows. Furthermore, carcasses of fast growing pigs were fatter (P<0.05) than those of slower growing ones. Loin muscle pH, drip loss and reflectance values did not vary significantly with any of the treatments. Intramuscular fat was higher in barrows (P<0.05) than in gilts and soluble collagen content decreased with increasing weight (P<0.05). Muscle protein (%) increased (P<0.05) from 107 to 115kg and gilts had a higher (P<0.05) content than castrates. No evidence was found that increasing slaughter weight detracts from carcass characteristics or meat quality.     

Effect of lairage duration on rabbit welfare and meat quality

This study determined whether short (2 h) or long (8 h) lairage at an abattoir had an effect on plasma stress indicators (haematocrit, glucose, lactate, creatine phosphokinase and corticosterone), instrumental meat quality (pH24, water holding capacity, colour, raw and cooked texture) and sensory meat quality (using a trained sensory panel) in rabbits. The effect of the position of the animals on a multifloor rolling cage stand during lairage was also assessed. Lairage time had a significant effect on blood stress indicators, but only a slight effect on meat quality traits. A lairage duration of 6–8 h is recommended.     

Effects of genotype, level of supplementation, and organic chromium on growth performance, carcass, and meat traits grazing lambs

The aim of the present study was to evaluate the effects of Suffolk×Dorper (SD) and Rambouillet (R) lamb genotypes, dietary supplementation, and organic chromium on growth performance, carcass, and meat traits in male lambs grazing ryegrass pasture. SD lambs had heavier cold carcass (HCW) and better carcass yield (CY) and rib eye area at 12th rib (RA) than R lambs; R had larger legs. Feed supplement increased average daily weight gain (ADG), slaughter live weight (SLW), hot carcass weight (HCW) and cold carcass weight (CCW), carcass yield, carcass length (CL), leg perimeter (LP), major thorax width (MTW), minor thorax width (MiTW), rib eye area and dorsal fat at 12th rib (DF12), and also decreased meat moisture. Organic chromium reduced dorsal fat at 12th rib and meat fat content.     

Effect of vaccination against gonadotrophin-releasing factor on growth performance, carcass, meat and fat quality of male Duroc pigs for dry-cured ham production

The aim of this study was to compare production, carcass and meat quality parameters, boar taint compounds and fat composition of green and dry-cured hams, between immunocastrated (IM), surgically castrated (CM) and female (FE) Duroc purebred pigs (n=75, 138.7±8.27kg). Liveweight and fat and muscle thicknesses were measured and average daily gain was calculated during growth. Carcass, meat and fat quality parameters were measured. Immunocastrated grew faster than CM or FE after the second dose of vaccine. IM had the lowest dressing percentage but similar % of ham and carcass lean to FE and CM. The effect of the immunocastration on carcass fatness depended on the location, did not affect fat and meat quality and reduced skatole and androstenone levels. Both in green and dry-cured ham, immunocastration slightly altered FA composition. Thus, Duroc pigs vaccinated with Improvac are suitable for the production of high quality dry-cured ham.     

Effect of lipid type on growth performance,meat quality and the content of long chain n − 3 fatty acids in pork meat

The aim of the present study was to produce pork with enhanced nutritive value for humans, both in terms of fatty acid profile (mainly long chain n − 3 fatty acids by feeding fish oil) and selenium. Forty-eight female pigs were allocated to one of six treatment groups: animal by-products and plant feedstuffs with tallow, plant feedstuffs with a blend of soybean oil and linseed oil with or without a supplement (CLA, selenium, vitamin E and vitamin C), plant feedstuffs with tallow and supplement, plant feedstuffs with fish oil and supplement. The diets containing the fish oil were fed up to either 49 days or 28 days before slaughter. The dietary treatments had no significant effects on growth performance, carcass characteristics and meat quality. When fish oil was included in the diet, higher levels of EPA, DPA and DHA were measured in the subcutaneous fat (up to 3.74%).     

Growth performance,carcass and meat quality of the Celta pig crossbred with Duroc and Landrance genotypes

The Celta pig is a native breed adapted to the north of Spain and extensive production system. The objective was to study the effects of sex and crossbreeding on carcass characteristics and meat quality. Samples were taken from longissimus dorsi muscle of 52 pigs of three different groups [Celta pure breed (C), Celta crossed with Landrace (C × L) and Celta crossed with Duroc (C × D)].