The Effect of Birth Weight on Fattening Performance, Meat Quality, and Muscle Fibre Characteristics in Lambs of the Karayaka Native Breed.

This investigation aimed to assess the influence of birth weight on post-weaning fattening performance, meat quality, muscle fibre characteristics, and carcass traits in Karayaka lambs. The study categorized the lambs into three distinct groups based on birth weight: low birth weight (LBW), medium birth weight (MBW), and high birth weight (HBW). Throughout the fattening phase, the lambs were given ad libitum access to food and water, culminating in the slaughter at the end of the study. Following slaughter, warm and cold carcasses were weighted, and specific muscles (longissimus thoracis et lumborum [LTL], semitendinosus [ST], and semimembranosus [SM]) were isolated for the evaluation of muscle weights, muscle fibre types (Type I, Type IIA, and Type IIB), and muscle fibre numbers. Carcass characteristics were also determined, including eye muscle (LTL) fat, loin thickness, and meat quality characteristics, such as pH, colour, texture, cooking loss, and water-holding capacity. The statistical analysis revealed highly significant differences among the experimental groups concerning muscle weights and warm and cold carcass weights (p < 0.01), with the lambs in the HBW group exhibiting a notably higher carcass yield (in females: 45.65 ± 1.34% and in males: 46.18 ± 0.77%) and LTL, ST, and SM (except for female lambs) muscle weights than the lambs in LBW group (p < 0.01). However, apart from the texture of LTL and ST muscles, no significant differences in meat quality parameters were observed among the treatment groups (p > 0.05). Notably, the birth weight of lambs did not impart a discernible effect on the total number and metabolic activity of muscle fibres in LTL, ST, and SM muscles. Nonetheless, a noteworthy distinction in the fibre area of Type I fibres in the LTL muscle of male lambs (LBW: 30.4 ± 8.9, MBW: 29.1 ± 7.3 and HBW; 77.3 ± 15.4) and in the ST muscle of female lambs (LBW: 44.1 ± 8.1, MBW: 38.8 ± 7.7 and HBW: 36.9 ± 7.1) were evident among the birth weight groups (p < 0.05). The study also found that the mean fat thickness values of eye muscles in Karayaka lambs, as obtained by ultrasonic tests, were below the typical range for sheep. In synthesis, the outcomes of this study underscore the considerable impact of birth weight on slaughtered and carcass weights, emphasizing the positive association between higher birth weights and enhanced carcass yield. Remarkably, despite these pronounced effects on carcass traits, the birth weight did not demonstrate a statistically significant influence on meat quality or overall muscle fibre characteristics, except for the area of Type I fibres in the LTL muscle. This nuanced understanding contributes valuable insights into the intricate relationship between birth weight and various physiological and carcass parameters in Karayaka lambs undergoing post-weaning fattening.

Determination of the effect of pre-mating weight and placental characteristics on birth weight in Karayaka sheep.

The aim of this study was to determine the effect of the pre-mating weight and placental characteristics on birth weight. Data were collected from 62 Karayaka ewes and 70 Karayaka lambs. The placental characteristics considered were placental weight, placental area and the number of cotyledons. The Pearson correlation coefficient was used for statistical comparison and the determination of relationships between variables. In addition, correlation coefficients between live weights and placental characteristics were determined. The average birth weight (BW), pre-mating weight (PMW), placental weight (PW), placental area (PA) and cotyledon number (CN) values were 4.37 ±â€¯0.70 kg, 50.22 ±â€¯5.63 kg, 362.51 ±â€¯118.42 g, 994.18 ±â€¯312.76 cm2 and 56.93 ±â€¯8.06, respectively. BW had positive correlations with PMW (0.147), birth type (BT) (0.643), PW (0.604), PA (0.323) and CN (0.161) (P < 0.05). BW had negative correlations with maternal age (MA) (-0.119) (P < 0.05). PMW had positive correlations with maternal age (MA) (0.237) (P < 0.05). PMW had negative correlations with S (sex) (-0.003), PW (-0.049), PA (-0.067) and CN (-0.080) (P > 0.05).

Macromolecules Influence Cellular Competence and Expression Level of IGFs Genes in Bovine Oocytes In Vitro.

In vitro maturation (IVM) of mammalian oocytes, which influences subsequent in vitro development of embryos, is affected by the macromolecule content in culture media for the success of oocyte maturation competence, in which the cytoplasmic and nuclear reprogramming events occur. The insulin-like growth factor family (IGFs) promotes the maturation of bovine oocytes and the expansion of cumulus cells and also inhibits apoptosis. This study was, therefore, designed to examine the effects of macromolecules (bovine serum albumin, BSA; fetal calf serum, FCS; and polyvinyl alcohol, PVA) on in vitro nuclear maturation, total cellular protein, glutathione peroxidase (GPx) enzyme activity, and the gene expression level of IGF1, IGF2, and their receptor in bovine oocytes. Oocytes obtained from bovine ovaries were cultured in bicarbonate-buffered medium 199 supplemented with 4 mg/mL BSA, 10% FCS, 1 mg/mL PVA, and without macromolecule supplement (control) during 22 h in the air with a humidified atmosphere and 5% CO2 at 38.5 °C temperature. Supplementation of BSA and FCS increased (χ2 = 9.84; p < 0.05) the percentages of oocytes that reached metaphase II compared to the control and PVA. The amount of protein per ml of cell extracts of oocytes matured in FCS supplemented culture media was higher (p < 0.05) than the oocytes in the PVA and control. The levels of GPx enzyme activity in cell extracts isolated from oocytes in each experimental group did not change over time, but the GPx enzyme activity in oocytes matured in PVA-supplemented culture media was lower (p < 0.05) than in oocytes in the other experimental groups. Transcript for the IGF1 gene was not detected in all experimental groups, but the supplementation of BSA and FCS significantly elevated the transcript level of the IGF2 gene. In addition, the maturation of oocytes with BSA-supplemented media increased the transcript level of the IGF1R gene, whereas the transcript level of the IGF2R gene was similar among macromolecule supplementation groups. The current study concluded that BSA and FCS could improve in vitro bovine oocyte development due to supporting nuclear maturation and increasing the total cellular protein content, GPx enzyme, and transcript activity.

Growth and Slaughter Characteristics of Weaning Male Kids of Turkish Native Goat Breeds.

There is little knowledge about the carcass potential of Turkish native goat breeds raised under different rearing conditions. It is necessary to compare the carcass characteristics of these breeds to minimize the effect of the rearing conditions. Therefore, this study aims to compare the growth, slaughter, and carcass characteristics of male kids at weaning age to eliminate the impact of rearing conditions. Kids born to Angora (n = 6), Hair (n = 6), Honamli (n = 6), and Kilis (n = 6) Turkish native goat breeds, ranging in age from 2-3 years, were slaughtered at 90 days of weaning age and carcass characteristics were determined immediately. There were differences (p < 0.05) among breeds in terms of birth weight (BW) and daily weight gain (DWG) from birth to weaning age. Honamli kids had higher BW and DWG than those of other breeds (p < 0.05). Similarly, carcass weights (hot-cold) and yields (hot-cold) of Honamli kids were higher compared to kids born to other breeds (p < 0.05). Additionally, Honamli and Hair kids had higher longissimus-dorsi (LD), and semitendinosus (ST) muscle weights compared to Kilis and Angora kids. Interestingly, Kilis kids had lower BW and DWG than those of other breeds (p < 0.05). There were significant differences (p < 0.05) among breeds in terms of non-carcass parts and organ weights. Positive correlations were calculated between cross-sectional area and weight (r = 0.793; p < 0.01), length and weight (r = 0.723; p < 0.01), and depth and weight (r = 0.698; p < 0.01) in LD muscle of all kids. A similar correlation trend was calculated for the ST muscle (cross-sectional area and weight; r = 0.699; p < 0.01, length and weight; r = 0.751; p < 0.01, and depth and weight; r = 0.528; p < 0.05) in all kids. In conclusion, the present study results showed that Honamli kids could be used for fattening material due to their good carcass quality compared to other native breeds.

Placental Characteristics Classification of Various Native Turkish Sheep Breeds.

The aim of this study was to classify placental characteristics of Akkaraman, Morkaraman, Karayaka, Awassi, Malya, and Bafra sheep breeds using the hierarchical clustering method. In total, 240 individual data records were used as experimental material. Placental characteristics such as total cotyledon surface area, small and large cotyledon length, small cotyledon depth, etc. were used as explanatory variables to classify the breeds' characteristics. Hierarchical clustering was used with the nearest neighbour method with Euclidean distance in order to classify the sheep breeds' variations. As a result, six breeds were separated into three clusters: the first cluster consisted of Bafra, Karayaka, and Awassi breeds; the second consisted of Akkaraman and Malya breeds; and the third cluster included only the Morkaraman breed. Bafra and Karayaka were pointed as the nearest breeds, with a similarity of 98.7% in terms of placental characteristics. The similarity rate of the Akkaraman and Malya breeds was at a level of 97.5%, whereas it was 96.8% for Bafra, Karayaka, and Awassi breeds. The similarity of Akkaraman, Karayaka, Awassi, Malya, and Bafra sheep breeds was estimated as 95.7%. The overall similarity was found to be at a level of 93.2% among sheep breeds. The outcomes of the study might be useful as a selection tool for reproductivity and can be used to select the breed to be reared.

Meat production characteristics of Turkish native breeds: II. meat quality, fatty acid, and cholesterol profile of lambs.

The study conducted a comparison of meat quality, fatty acid profile, and cholesterol amounts of longissimus dorsi (LD) and semitendinosus (ST) muscles of male lambs born to Turkish indigenous sheep breeds raised under intensive conditions. A total of 36 singleton male lambs were used as experimental animals of the Akkaraman (A), Morkaraman (M), Awassi (IW), Karayaka (KR), Kivircik (KV), and Middle Anatolian Merino (MAM) pure breeds. All lambs were fed the same diet until they reached a target weight of 40 kg weight. After the feeding period, all lambs were slaughtered and LD and ST muscle samples were collected to determine meat quality traits, fatty acid profile, and cholesterol amounts. Although there were no significant differences between lambs in terms of the fatty acid profile of LD and ST muscles, KR lambs had a higher cholesterol content in both muscles in comparison with the lambs born to other breeds ( p < 0.05 ). While water-holding capacity, dripping loss, pH, color, dry matter, ash, and intramuscular fat values of ST muscles showed differences among breeds ( p < 0.05 ), dripping loss, pH, cooking loss, color, dry matter, ash, protein, and intramuscular fat values of LD muscles differed between breeds ( p < 0.05 ). The data of the current study indicated that meat quality characteristics and cholesterol contents of Turkish indigenous breeds showed differences, and these differences may be used for alternative lamb meat production for the consumer.

Estimates of (co)variance components for direct and maternal effects on birth weight of Karayaka lambs.

The purpose of this study was to estimate the genetic parameters for birth weight of Karayaka lambs by separating direct genetic, maternal genetic, and maternal permanent environmental effects. Records of 1013 Karayaka lambs born between 2005 and 2010 were analyzed. Six different animal models were examined, all including direct additive genetic variance and various combinations of genetic and environmental maternal effects. The most appropriate model was chosen based on log-likelihood ratio tests. Since model 1 had the smallest likelihood value, it was chosen as the best model in this study. Depending on the model, direct heritability varied from 0.37 to 0.55 and maternal heritability ranged from 0.08 to 0.20 for birth weight.

Fattening performance, slaughter, carcass and meat quality traits of Karayaka lambs.

In order to verify the fattening performance, slaughter and carcass characteristics and to investigate the changes in some meat quality traits of Karayaka lambs weaned at 3 months of age, 39 lambs (23 males and 16 females) were used as experimental animals. The lambs were fed a concentrate mixture and alfalfa hay (120 and 168 g crude protein and 2,700 and 1,951 ME/kg, respectively) for a period of 60 days of fattening period. Male lambs were superior (p < 0.05) to female lambs in terms of daily weight gain (270.4 vs. 205.4 g; SEM = 9.46), hot and cold carcass weights (16.7 and 16.0 vs. 14.1 and 13.4 kg, respectively; SEM = 0.35), intra-muscular fat ratios (1.9% vs. 2.5%; SEM = 0.12) and dripping loss of semitendinosus muscle 3 days postmortem (8.1% vs. 10.2%; SEM = 0.36). The relative weights of some organs, the meat quality traits (pH, cooking loss, shear force, CIELab colour characteristics) and proximate analyses (dry matter, protein and ash) of longissimus dorsi and semitendinosus muscle samples from lambs were not affected by sex (p > 0.05). Dripping loss, pH and colour characteristics were affected by storage time (p < 0.05). These results provide a basic understanding of performance and meat quality of Karayaka sheep which may have potentials in improving sheep production using an indigenous sheep breed in Turkey.

Introducing the Karayaka sheep breed with its traits and influencing factors.

This study was planned to express the detailed traits of Karayaka sheep reared in Tokat province, also influencing factors on the traits were evaluated. While year effect was significant on 8 weeks weight, scanning weight, fat depth and muscle area, all the evaluated traits including birth weight and muscle depth were significantly affected by season (p < 0.05). Dam age was significant on birth weight (p < 0.05). Birth weight and 8 week weight were significantly affected by sex and birth type. Sex effect has been appeared on muscle depth while birth type effect has been detected on scanning weight (p < 0.05). While the strongest phenotypic correlation coefficient was detected between muscle depth and muscle area, the weakest ones were found between birth weight and scanning traits.