Meat quality characteristics of Turkish indigenous Hair goat kids reared under traditional extensive production system: effects of slaughter age and gender

Evaluation of carcass traits, meat quality and the expression of lipid metabolism-related genes in different slaughter ages and muscles of Taihang black goats

OBJECTIVE

This study was conducted to investigate the effect of slaughter age on carcass traits, meat quality, and the relative mRNA levels of lipid metabolism-related genes in different muscles of Taihang black goats.

METHODS

In this study, the triceps brachii (TB), longissimus dorsi (LD) and gluteus (GL) muscles of 15 grazing Taihang black goats slaughtered at the age of 2, 3, and 4 (designated as 2-year-old, 3-year-old, and 4-year-old, respectively) were collected. The differences in carcass shape, meat quality, amino acid composition and lipid metabolism gene expression among Taihang black goats of different ages and from different plant parts were compared.

RESULTS

Compared with goats at other ages, goats slaughtered at the age of 4 had greater live and carcass weights, meat weights, bone weights and skin areas (p<0.05). LD in the 4-years-old had the lowest cooking loss and moisture content. The crude protein content in the LD of 2-year-old was significantly greater than that in the other age group, and at the age of 2, the LD had the highest crude protein content than TB and GL. The highest fat content was in LD, followed by TB, for goats slaughtered at the age of 4. Eight out of 9 essential amino acids had higher content in the TB compared with other muscles, regardless of age. The total essential amino acid content was highest in the 4-year-old and lowest in the GL muscle at the age of 3. The sterol regulatory element-binding protein-1c (SREBP-1c) and adipose triglyceride lipase (ATGL) genes were significantly more abundant in the TB muscle than in the other muscles for goats slaughtered at the age of 2. At the age of 4, the ATGL and peroxisome proliferator-activated receptor γ (PPARγ) genes were significantly more abundant in the GL than in the LD, while the fatty acid synthase (FAS) genes were significantly less abundant in the GL than in the other muscles. Similarly, compared with those in goats of other ages, the relative mRNA expression levels of the FAS and heart-type fatty acid binding protein (H-FABP) genes in goats slaughtered at the age of 4 were the highest, and the relative mRNA expression of the PPARγ gene was the lowest (p<0.05). The relative mRNA expression of the H-FABP and FAS genes was positively correlated with the intramuscular fat (IMF) content, while the relative mRNA expression levels of the PPARγ and ATGL genes was negatively correlated with the IMF content.

CONCLUSION

Overall, a better nutritional value was obtained for TB from 4-year-old goats, in which the total essential amino acid and fat contents were greater than those of other muscles. The comprehensive action of lipid metabolism genes was consistent with that of the IMF content, among which the FAS, H-FABP, PPARγ, and ATGL genes had positive and negative effects on the process of IMF deposition in Taihang black goats.

Comparison of muscle fiber characteristics and meat quality between newborn and adult Haimen goats

Goat meat is popular with consumers for its rich nutritional content. Muscle fiber characteristics have been shown to play a crucial role in determining the quantity and quality of meat. However, little is known about the temporal changes in muscle fiber characteristics and meat quality during growth in goats. In this study, muscle fiber type, fiber diameter, fiber cross-sectional area (CSA), glycolytic potential (GP), meat pH, and meat color were analyzed in the gastrocnemius (GAS), gluteus medius (GM), biceps brachii (BB), longissimus lumborum (LL) muscles from newborn (NHMG) and adult (AHMG) Haimen goats. The distribution of type I and type Π fiber in goats is not consistent across the four muscles and undergoes alterations with age. The diameter and CSA of the muscle fibers were similar among the four NHMG muscles. However, in AHMG, the LL muscle had the largest fiber in terms of both diameter and CSA, followed by BB, GM, and GAS muscles. Moreover, the CSA of type Π fibers was higher than that of type I fibers in both NHMG and AHMG. GP values ranged from 90 to 140 umol/g across the muscle and no significant differences were observed. AHMG had a higher pH level and a* value, but lower L* and b* values than NHMG. Overall, our findings enhance our understanding of the changes in muscle fiber type and meat quality during the growth in Haimen goats and provide a basis for future research on the development and transformation of muscle fibers in goats.

Physicochemical Properties of Black Korean Goat Meat with Various Slaughter Ages

This study was conducted to analyze the physicochemical properties of black goat meat according to the slaughter age (3, 6, 9, 12, 24, 36 months). The moisture content tended to decrease, whereas the fat content, pH, and free amino acid composition tended to increase with increasing slaughter age. The collagen content increased significantly with the increasing slaughter age (p < 0.05). The cooking yield showed a tendency to increase up to 12 months of age, and there was no significant difference after 12 months of age. In all mineral contents, the sample for 12 months of age showed higher values than the others. Considering fatty acid composition, the saturated fatty acid content of the 12-month sample had a lower value than the other samples. However, the unsaturated fatty acid of the 12-month sample had higher values than the other samples. Therefore, the best slaughter age for black goats occurs at 12 months of age when nutrition is excellent.

The Effect of Slaughter Age on Meat Quality of Male Kids of the Polish Carpathian Native Goat Breed

The native breed of Carpathian goats, once abundant in the foothills of Poland, practically died out and was replaced by other, more efficient breeds. As a result of reintroduction activities and its inclusion in the genetic resources program, breeding was restored. The dynamically developing population of Carpathian goats is an extremely valuable element of biodiversity and a potential for the development of the market for its products, including goat meat. The study aimed to compare the carcass measurements and the quality and composition of meat from male kids of the Polish Carpathian native goat breed slaughtered at the ages of 9 and 12 months. Muscle samples were taken from the leg (m. biceps femoris) to determine the meat chemical composition and physicochemical and sensory parameters, as well as the fatty acid profile. The dressing percentage was higher in older kids (41.27%) than in younger ones (37.89%), as well as final weight and cold carcass weight. The weight of valuable cuts such as the loin and leg differed between groups, and it was significantly higher in 1-year-old kids. No differences were found in basic ingredients, such as moisture, protein, ash and vitamins A and E, depending on the kids’ slaughter age. The fat concentration was significantly higher in the group of younger kids. Significant differences occurred in relation to the physicochemical parameters, fatty acid profile and organoleptic properties. The findings demonstrated that the meat of older kids was characterised by darker colour and a slightly higher pH, and it contained a higher concentration of hypocholesterolemic fatty acids (DFA) and a more favourable DFA/OFA ratio. Roasted meat from the Carpathian kids scored high marks in the organoleptic assessment and the meat obtained from older animals was rated higher.

Influence of breed on selected quality parameters of fresh goat meat

The potential of goats to produce a high-quality meat is mainly reflected in their healthy fats, low calorie intramuscular fats, saturated fats, and, especially, their high ratios of unsaturated (UFA) and saturated (SFA) fatty acids, as well as hypocholesterolemic and hypercholesterolemic fatty acids. The aim of this study was to collect and compare meat quality parameters for domestic Balkan, Alpine and Saanen goats of the same age. Samples for all tests were taken from musculus gluteus superficialis. Chemical composition, pH value, fatty acid composition, content of volatile compounds, color and overall sensory quality (appearance, texture and smell) were determined. In chemical composition, moisture, fat, protein and ash varied significantly between each of the examined groups as opposed to pH values. Furthermore, among all the examined groups a significant difference was found for fatty acids and volatile compounds. Determined ratio of polyunsaturated fatty acids (PUFAs) to SFAs was 0.089, 0.085 and 0.071 for Balkan, Alpine and Saanen goat meats, respectively. Regarding that ratio, Saanen goat meat had the most favorable characteristics. Saanen goat meat showed the highest nutritional value. On the other hand, Balkan goat meat had the lowest intramuscular fat content. Measurements of the meat color from all three groups, as well as overall acceptability, showed significant differences between breeds. Obtained results point to the impact of breed on chemical composition and fatty acid profile of goat meat.

Fatty acid, chemical, and tissue composition of meat comparing Santa Inês breed sheep and Boer crossbreed goats submitted to different supplementation strategies

To compare the fatty acid (FA) composition, and chemical and tissue composition of meat, 24 uncastrated males, 12 sheep of the Santa Inês breed, and 12 crossbred goats (F1 Boer × undefined breed) with the weight of 24.3 ± 2.38 kg. The animals were distributed in a randomized block design and treatments were arranged in a 2 × 2 factorial design, two small ruminant species/breed (Boer crossbreed goat × Santa Inês breed sheep), and two supplementation strategies (energy × protein energy). There was not an interaction between the small ruminant species and the supplementation on average daily gain, tissue composition, chemical composition, or FA profile of the longissimus lumborum muscle. Sheep presented greater weight and yield of fat in the subcutaneous, intermuscular, and total depots than goats, which results in better finishing of the sheep for slaughter. Goat meat presented a lower lipid concentration than sheep meat. The protein-energy supplementation increased oleic acid, ΣUFA, ΣMUFA, hypocholesterolemic/ Hypercholesterolemic index, and enzymatic activity Δ9-desaturase C18 and decreased SFA capric acid in the muscle when compared with energetic supplementation. In Caatinga biome conditions, Boer crossbreed goats meat has a lower concentration of lipids and a healthier FA composition compared with Santa Inês breed sheep because it has a lower SFA and greater PUFA content, which are sources of n-3 and n-6, which may contribute to the reduction of blood cholesterol (LDL). In addition, protein-energy supplementation also improved the quality of animal fat compared with supplementation only with the energetic concentrate, regardless of species.

Molecular characterization and different expression patterns of the FABP gene family during goat skeletal muscle development

The FABP (adipocyte fatty acid-binding protein) genes play an important role in intracellular fatty acid transport and considered to be candidate genes for fatness traits in domestic animal. In this study, we cloned the cDNA sequences of goat FABP family genes and their expression patterns were detected by semi-quantitative RT-PCR and quantitative real time RT-PCR. Expression analysis showed that goat FABP1 gene was predominantly expressed in liver, kidney and large intestine. While FABP4 was widely expressed in many tissues with a high expression level was observed in the fat, skeletal muscle, stomach and lung. Notably, FABP2 gene was expressed specifically in small intestine. Moreover, goat FABP3 was expressed at 60 day with the highest level, then significantly (p < 0.01) decreased at the 90 day. No significant expression differences were observed in longissimus dorsi muscles among 3 day, 30 day and 60 day. Goat FABP4 was expressed at 3 day with the lowest level, then significantly (p < 0.01) increased to a peak at the 60 day. In addition, a significant relationship between FABP3 mRNA expression levels and intramuscular fat (IMF) content was observed. These results suggest that the FABP3 and FABP4 may be important genes for meat quality and provides useful information for further studies on their roles in skeletal muscle IMF deposit.

Expression patterns of peroxisome proliferator-activated receptor gamma 1 versus gamma 2, and their association with intramuscular fat in goat tissues

Intramuscular fat (IMF) shortage causes the lack of juiciness and tenderness of goat meat, while peroxisome proliferator-activated receptor gamma 1 (PPARγ1) and gamma 2 (PPARγ2) play key roles in lipid metabolism. Nevertheless, their expression patterns and the relationship with IMF have been poorly exposed. Using quantitative polymerase chain reaction (qPCR), classical Soxhlet extraction, and in situ hybridization, we demonstrated that among 13 goat tissues, expression of PPARγ1 was dramatically higher than that of PPARγ2 except for lung. We further demonstrated the expression patterns of PPARγ1 and PPARγ2 and their negative association with intramuscular fat content in three goat muscles with kids growing. Meanwhile, PPARγ expression was located in the connective tissues. These results suggest that PPARγ1 is rather active for most tissues of goat, and closely related with the muscular fat metabolism during early postnatal life, but a more direct proof remains to be provided.