The effect of dietary energy content on quality characteristics of Boer goat meat

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.

Growth Performance, Blood Metabolites, Carcass Characteristics and Meat Quality of Lambs Fed Diets Containing Different Energy Levels Supplemented with Rumen-Protected Choline

This study aimed to examine the effects of metabolizable energy (ME) level and rumen-protected choline (RPC) supplementation on the growth performance, carcass characteristics, meat quality, serum energy, lipid, and protein profiles of Karayaka lambs. Twenty-eight Karayaka lambs, with an initial body weight (BW) of 26.85 ± 0.26 kg, were randomly assigned (2 × 2 factorial design) to one of four dietary treatments with two levels of ME (optimum: 2750 or low: 2500 kcal ME/kg dry matter) and two levels of RPC (0 or 4 g/d/lamb). Lambs of each group were housed in individual pens. The experiment lasted 66 d, with the first 10 d consisting of acclimation and the next 56 d of the formal experimental period. The data on BW, dietary matter intake (DMI), and serum glucose concentrations confirm that our model successfully induced low energy using 250 kcal/kg less energy than the optimum level. RPC supplementation did not significantly affect average daily DMI, total average daily gain (ADG), or feed conversion ratio (FCR) at any energy level. Additionally, there was no substantial effect on carcass characteristics, meat quality, serum lipids, energy metabolism indicators, and liver function parameters. There was also no interaction effect of RPC × ME on the parameters tested. However, at 56 d into the experiment, the interaction effect of RPC × ME on serum urea-N was highly significant, and RPC supplementation led to lower serum urea-N levels (p = 0.001). These results suggest that while RPC supplementation did not enhance overall performance and carcass characteristics in Karayaka lambs, it may play a role in modulating nitrogen metabolism, as indicated by the significant reduction in serum urea-N levels.

Effects of Different Dietary Energy Levels on Development, Quality of Carcass and Meat, and Fatty Acid Profile in Male Lambs

This experiment was conducted to study the effects of dietary energy level on the growth performance and meat quality of weaned Alpine Merino lambs. The study ran for a total of 104 days (20-day pretrial, 84-day trial). From three groups of test lambs, we randomly selected ten lambs per group to determine slaughter performance, meat quality characteristics, and organ indexes. The slaughter performances of the lambs improved as the dietary energy level increased. The live weight before the slaughter of the lambs was significantly higher in the high group than in the low and medium groups. The carcass weight was significantly higher in the high group than in the low group. Dietary energy level had little effect on the organ weight of lambs. Meat quality differed among the three dietary energy levels. The muscle yellowness and redness scores decreased significantly as the energy levels increased. The C18:0, C21:0, C20:1, C18:2n6c, and C20:2 contents in the muscle were significantly higher in the high group than in the medium and low groups. The C18:3n6 content in the muscle was significantly higher in the low group than in the medium group. The C20:5n3 content in the longissimus dorsi was significantly higher in the high group than in the medium and low groups. The monounsaturated and unsaturated fatty acid contents in the muscle were significantly higher in the high group than in the low group. A dietary energy level of 10.5 MJ/kg is suitable for fattening weaned male Alpine Merino lambs.

Feeding regimens affecting carcass and quality attributes of sheep and goat meat - A comprehensive review

Sheep and goats can efficiently convert low quality forage into high-quality meat which contains specific nutrients and quality traits. Carcass traits and quality attributes of sheep and goat meat depend upon several factors and one of most effective strategies amongst these is feeding regimens. In this review, the major aspects of feeding regimens affecting growth rate, carcass traits and quality attributes of sheep and goat meat are thoroughly discussed, with a particular focus on physical-chemical composition, flavor profile, and fatty acid (FA) profile. Grazing lambs and kids receiving concentrate or under stall-feeding systems had greater average daily gain and carcass yield compared with animals reared on pasture only. However, growth rate was higher in lambs/kids grazing on pastures of improved quality. Moreover, the meat of grazing lambs receiving concentrate had more intense flavor, intramuscular fat (IMF) content, and unhealthy FA composition, but comparable color, tenderness, juiciness, and protein content compared to that of lambs grazed on grass only. In contrast, meat of concentrate-fed lambs had more intense color, greater tenderness and juiciness, IMF and protein contents, and lower flavor linked to meat. Additionally, the meat of kids grazed on concentrate supplementation had higher color coordinates, tenderness, IMF content and unhealthy FA composition, whereas juiciness and flavor protein content were similar. In contrast, kids with concentrate supplementation had superior color coordinates, juiciness, IMF content and unhealthy FA composition, but lower tenderness and flavor intensity compared to pasture-grazed kids. Thus, indoor-finished or supplemented grazing sheep/goats had higher growth rate and carcass quality, higher IMF content and unhealthy FA composition compared to animals grazed on grass only. Finally, supplementation with concentrate increased flavor intensity in lamb meat, and improved color and tenderness in kid meat, whereas indoor-fed sheep/goats had improved color and juiciness as well as reduced flavor compared to pasture-grazed animals.

Effects of different forage proportions in fermented total mixed ration on muscle fatty acid profile and rumen microbiota in lambs

Objective

The objectives of this study were to evaluate the effects of different forage proportions in the fermented total mixed ration (FTMR) on growth performance, muscle fatty acid profile, and rumen microbiota of lambs.

Methods

Thirty 6-month-old small tail Han sheep × Ujumqin lambs with initial body weight (BW) of 27.8 ± 0.90 kg were selected for the test and divided into two groups of 15 sheep in each treatment (three pens per treatment and five lambs per pen) according to the principle of homogeneity. Two isoenergetic and isonitrogenous diets were formulated according to the NRC. The diet treatments were designed as (1) OH treatment containing 25% alfalfa hay and 35% oat hay, and (2) AH treatment containing 35% alfalfa hay with 25% oat hay. The forage-to-concentrate ratio for both diets was 65: 35 (DM basis). Three replicates were randomly selected from each treatment to determine growth performance, fatty acid profile and rumen bacterial communities in lambs.

Results

Results revealed no statistically significant (p > 0.05) differences in dry matter intake and average daily gain between the two diet groups. Cholesterol and intramuscular fat were significantly (p > 0.05) higher in the AH group, while no statistically significant difference (p > 0.05) was found in pH24 value. The muscle fatty acid compositions of lambs were obviously (p < 0.05) influenced by the diet treatments. Compared with the OH group, the C16:1, C17:0, and C20:3n6 contents were higher (p < 0.05) in the AH group, whereas the content of C18:1n9c, C20:1, C18:3n3, and C22:6n3 was obviously (p < 0.05) increased in the OH group. The monounsaturated fatty acid (MUFA) contents were significantly higher in the OH group, whereas no significant differences (p > 0.05) were detected in saturated fatty acid (SFA) and polyunsaturated fatty acid (PUFA) contents among the two diet treatments. Bacterial composition was generally separated into two clusters based on principal coordinate analysis, and the OH group had a higher Shannon index. The relative abundance at the genes level of the Rikenellaceae_RC9_gut_group was obviously (p < 0.05) increased in the AH group and the relative abundances of Prevotella_1, Fibrobacter, and Bacteroidales_UCG_001_unclassified were obviously (p < 0.05) enriched in the OH group. Integrated correlation analysis also underscored a possible link between the muscle fatty acid compositions and significantly altered rumen microbiota.

Conclusion

Overall, oat-based roughage in FTMR could promote a beneficial lipid pattern in the Longissimus lumborum muscles of lambs. These findings provide a potential insight into diet effects on fatty acid profile and the rumen microbiome of lambs, which may help make decisions regarding feeding.

Comparative Quality Traits, Flavor Compounds, and Metabolite Profile of Korean Native Black Goat Meat

Although goat meat has several health benefits than other red meats but comsumers reluctant it due to its unpleasant flavor. This study aimed to investigate the odorant of goat meat as well as compare the quality traits of meat regarding sex status. The loin meats [non-castrated male (NCM), castrated male (CM), and female (FM)] were collected and stored at 4°C in a laboratory refrigerator and analyzed on the 1^st, 5^th, and 8^th consecutive days. The moisture content was the lowest and the protein content was highest in FM (p<0.05). Fat and ash content in NCM and FM were similar while lowest in CM. The CIE L* was significantly higher in NCM, but there were no significant differences of CIE a* and CIE b* within groups at initial day. The color intensity increased on the 5^th storage day and decreased again after the 8^th storage day, except in NCM. NCM displayed the highest thiobarbituric acid reactive substances value (p<0.05), whereas CM displayed a higher pH value than other groups throughout the storage period. Indole levels were the highest in NCM (0.031 mg/kg); however, skatole levels were not significant differences across all treatments (p>0.05). No significant difference was observed in the fatty acid composition between NCM and CM (p>0.05), whereas a significant difference was observed in FM (p<0.05). Most of the water-soluble metabolites showed significant differences between sexes. Overall, sex status effects on quality properties of meat and castration can improve the overall sensory acceptance by reducing goaty flavor of Korean native black goat meat.

Insights into the trace Sr2+ impact on the gel properties and spatial structure of mutton myofibrillar proteins

Myofibrillar proteins (MPs) and the quality of meat strongly depend on the properties of MP gels, which in turn depend on several parameters that include the thermal history and the concentration of metal ions. Strontium element (Sr) widely exists in mineral water and is found as strontium ions (Sr²⁺), which is an essential trace element for humans. This study investigated the effects of trace Sr²⁺ on the structure-function relationship of mutton MPs, as well as their gels with water. Trace concentrations of Sr²⁺ were found to significantly alter the conformation of the MPs. An increase in Sr²⁺ concentration was associated with a reduction in the tightness and strength of the gel and a significant increase in its water-holding capacity As compared to the untreated control sample, the solubility, particle size, and the magnitude of the Zeta potential of the gels increased by 13.03 %, 12.62 %, and 19.73 %, respectively, whereas the water retention capacity and the gel strength increased by 23.13 % and 21.90 %, at a Sr²⁺ concentration of 5.0 mg/L. Molecular docking predicted an increase in ionic bonds and disulfide bonds because Sr²⁺ had a strong interaction with hydrophilic amino acids and acidic amino acids. The analysis of molecular forces further verified the significant facilitation of interactions between MP molecules with the induction of Sr²⁺. As compare to the untreated control group, the ionic and disulfide bonds increased by 141.17 % and 66.94 %, when treated with 5.0 mg/L Sr²⁺. These changes were likely due to the enhancement of protein-protein interactions caused by Sr²⁺, which could induce MP molecules to properly unfold and aggregate in gel formation. The results could provide a basis for improving the texture and the quality of meat and meat products.

Physicochemical Composition and Fatty Acid Profile of Goat Kids' Meat Fed Ground-Corn-Grain Silage Rehydrated with Different Additives

The effects of the replacement of dry ground corn (GC) with corn-grain silage rehydrated with water (RCSwater), cactus pear mucilage (RCSmucilage), and whey (RCSwhey) on the growth, physicochemical composition, and fatty acid profile of goat kids’ meat were investigated. Thirty-two crossbred goat kids (16.4 ± 2.50 kg initial weight) were assigned in a randomized block design with four treatments and eight repetitions. The NDF intake of goat kids fed with RCSmucilage was higher in comparison to RCSwater and RCSwhey (p = 0.0009). The dietary replacement of GC by RCSmucilage increased the final weight (p = 0.033) and meat-cooking losses (p = 0.0001) of kids. The concentrations of oleic (p = 0.046), 11,14-eicosadienoic (p = 0.033), and EPA (p = 0.010) were higher in the meat of kids fed with RCSmucilage and RCSwhey, and the α-linolenic concentration was higher (p = 0.019) for animals feeding with RCSmucilage. Meat from kids fed with RCSwhey presented the lowest ∑SFA and the highest ∑MUFA. In contrast, the ∑PUFA (p < 0.012) was higher for goats fed with RCSwater. The ∑ω3 (p < 0.0001) was higher in animals fed with RCSmucilage and RCSwhey. Desirable fatty acids were higher (p = 0.044) in animals fed with RCSmucilage and RCSwhey, and the atherogenicity (p = 0.044) and thrombogenicity (p < 0.0001) indexes were lower for goats fed the RCSwhey diet. The enzymatic activities of Δ9desaturase (C16) were higher (p = 0.027) in goat kids fed with GC and RCSmucilage, and Δ9desaturase (C18) was higher (p = 0.0497) when goats were fed with RCSmucilage and RCSwhey. Elongase activities were higher (p = 0.045) in goat kids fed with GC and RCSwater. The total replacement of GC by RCSmucilage is recommended in the diet of goat kids due to improvements in the weight gain and proportion of desirable fatty acids in the meat. In addition, RCSmucilage promoted better conservation of the silage at a lower cost when compared to commercial additives.

Metabolomics approach reveals high energy diet improves the quality and enhances the flavor of black Tibetan sheep meat by altering the composition of rumen microbiota

This study aims to determine the impact of dietary energy levels on rumen microbial composition and its relationship to the quality of Black Tibetan sheep meat by applying metabolomics and Pearson's correlation analyses. For this purpose, UHPLC-QTOF-MS was used to identify the metabolome, whereas 16S rDNA sequencing was used to detect the rumen microbiota. Eventually, we observed that the high energy diet group (HS) improved the carcass quality of Black Tibetan sheep and fat deposition in the longissimus lumborum (LL) compared to the medium energy diet group (MS). However, HS considerably increased the texture, water holding capacity (WHC), and volatile flavor of the LL when compared to that of MS and the low energy diet group (LS). Metabolomics and correlation analyses revealed that dietary energy levels mainly affected the metabolism of carbohydrates and lipids of the LL, which consequently influenced the content of volatile flavor compounds (VOCs) and fats. Furthermore, HS increased the abundance of Quinella, Ruminococcus 2, (Eubacterium) coprostanoligenes, and Succinivibrionaceae UCG-001, all of which participate in the carbohydrate metabolism in rumen and thus influence the metabolite levels (stachyose, isomaltose, etc.) in the LL. Overall, a high-energy diet is desirable for the production of Black Tibetan sheep mutton because it improves the mouthfeel and flavor of meat by altering the composition of rumen microbiota, which influences the metabolism in the LL.

Genome-Wide Selective Analysis of Boer Goat to Investigate the Dynamic Heredity Evolution under Different Stages

Boer goats, as kemp in meat-type goats, are selected and bred from African indigenous goats under a long period of artificial selection. Their advantages in multiple economic traits, particularly their plump growth, have attracted worldwide attention. The current study displayed the genome-wide selection signature analyses of South African indigenous goat (AF), African Boer (BH), and Australian Boer (AS) to investigate the hereditary basis of artificial selection in different stages. Four methods (principal component analysis, nucleotide diversity, linkage disequilibrium decay, and neighbor-joining tree) implied the genomic diversity changes with different artificial selection intensities in Boer goats. In addition, the θπ, FST, and XP-CLR methods were used to search for the candidate signatures of positive selection in Boer goats. Consequently, 339 (BH vs. AF) and 295 (AS vs. BH) candidate genes were obtained from SNP data. Especially, 10 genes (e.g., BMPR1B, DNER, ITGAL, and KIT) under selection in both groups were identified. Functional annotation analysis revealed that these genes are potentially responsible for reproduction, metabolism, growth, and development. This study used genome-wide sequencing data to identify inheritance by artificial selection. The results of the current study are valuable for future molecular-assisted breeding and genetic improvement of goats.

Gangba sheep in the Tibetan plateau: Validating their unique meat quality and grazing factor analysis

Gangba sheep are known for having typical sensory characteristics attributed to free range conditions and grazing on wild plants. The genuine Gangba mutton was selected as the experimental group, and the commercial Tibetan mutton was selected as the control group, the nutritive composition of basic chemical components, amino acids and fatty acids in mutton were investigated to correlate its unique meat quality and eating satisfaction. The results showed that fatty acids were significantly higher (P<0.05) in Gangba mutton than in commercial mutton, and the higher content of flavoring amino acids (glutamic acid and aspartame) were primarily responsible for the taste attributes umami of meat juices. Moreover, the trace elements analysis in mutton and grazing factors (forage, water source and soil) were conducted, to explain the source of essential trace elements in mutton. The concentrations of essential trace elements show that the Gangba mutton was a valuable source for highly available Cu and Zn in human nutrition, and well managed with few detected of toxicity metal. The concentrations of essential trace elements in mutton are closely related to the trace elements in environmental grazing factors. In conclusion, the congenital grazing conditions (a highly mineralized water resource, natural forages and clean soils) were shown to contribute to the unique meat characteristics of Gangba sheep.

Meat quality characteristics of lot-fed Australian Rangeland goats are unaffected by live weight at slaughter

The effects of live weight on carcass characteristics and meat quality of Australian Rangeland goats were determined. Fifty-two intact-male kid goats were fed Mitchell grass hay and finisher pellets ad libitum for 42 days. Prior to slaughter, kids were categorised into live weight groups: 'Heavy' (≈33.1 kg) or 'Light' ≈ 24.3 kg). Fifteen kids per group were randomly selected, slaughtered and carcass characteristics measured. The longissimus lumborum (LL) and the biceps femoris (BF) muscles were removed for quality measurements. The Heavy group had higher dressing, hindquarters, non-carcass component and offal percentages (P < 0.05). Live weight had no effect on proportion of carcass cuts, muscle meat colour, cooking loss, Warner-Bratzler shear force, total fat or ash (P > 0.05), but influenced the moisture and protein content in the LL and the moisture content in the BF (P < 0.05). The findings suggest that live weight of entire male Rangeland goats had no effect on meat quality characteristics.

Effect of Breed Types and Castration on Carcass Characteristics of Boer and Large Frame Indigenous Veld Goats of Southern Africa

Simple Summary

The purpose of this paper is to describe and compare the carcass characteristics of same-aged young wethers and bucks of Boer Goat (BG) and Indigenous Veld Goats (IVG: Cape Speckled and the Cape Lob Ear)—a collective name for the eco-types conserved by the Indigenous Veld Goat Society of South Africa. Results of this study showed that, under the same production conditions, IVG could have a similar potential for meat production. Carcass characteristics differed more between wethers and bucks than between breed types. Large frame Indigenous Veld Goat (IVG) bucks seemed particularly suited for meat production, due to higher meat yield that is leaner with lower subcutaneous and intramuscular fat, compared to the BG bucks and, in particular, to the wethers of both breed types. The wethers meat with increased subcutaneous and intramuscular fat could satisfy another consumer market segment that prefer a somewhat juicier and flavorsome meat—these aspects warrant further research. Development of the formal commercial market for goat meat would offer more diversity of species for red meat producers and especially benefit smallholder farmers who typically produce most of the goats in the world.

Abstract

Weaner male Boer Goats (BG; n = 36; 21 bucks and 15 wethers) and large frame Indigenous Veld Goats (IVG; n = 41; 21 bucks and 20 wethers) were raised on hay and natural grass ad libitum and the recommended amount of commercial pelleted diet to a live weight between 30 and 35 kg. Carcass quality characteristics (live weight, carcass weights, dressing %, chilling loss and eye muscle area) were measured. The right sides of the carcasses were divided into wholesale cuts and dissected into subcutaneous fat, meat and bone. Large frame Indigenous Veld Goat (IVG) wethers were slightly lighter than the IVG bucks with no significant difference observed between BG. Wethers compared to bucks had higher dressing %, subcutaneous fat % in all primal cuts, intramuscular fat %, kidney fat % and, overall, slightly less bone %. Some breed–wether interactions were noticed: IVG wethers were slightly lighter than the IVG bucks, but the IVG bucks tended to produce higher % meat compared to other test groups. Judged on the intramuscular fat % characteristics, it seems as if wethers should produce juicier and more flavorsome meat compared to bucks.

Carcass parameters and meat quality of Tibetan sheep and Small-tailed Han sheep consuming diets of low-protein content and different energy yields

Today, consumers are very health conscious and are more aware of the nutritional value of food, especially of meat, than they were in the past. The aim of this study was to evaluate the carcass parameters and meat quality of Tibetan sheep and Small-tailed Han sheep when consuming a diet of low-protein (~7%) and different energy yields (digestible energy, 8.21, 9.33, 10.45 and 11.57 MJ/kg) in the cold season. Twelve sheep of each breed were divided randomly into four treatments of different diets with three replicates per treatment per breed. Crude protein of the meat decreased linearly (p < .05), whereas energy increased linearly (p < .05) with an increase in energy level. Tibetan sheep tended to have a higher (p < .1) dressing percentage and rib eye area, while live body weight and hot carcass weight did not differ between breeds but increased linearly (p < .01) with an increase in energy level. Water holding capacity, as indicated by pressing loss and drip loss, did not differ between breeds and was not affected by dietary energy. The concentration of n-3 polyunsaturated fatty acids (PUFAs) was greater in Tibetan sheep meat but saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs) and n-6 PUFA did not differ between breeds. With an increase in energy content of the diet, SFA decreased (p < .05), whereas MUFA increased (p < .05). The n-6:n-3 PUFA ratio was lower (p < .001) in Tibetan sheep meat, while the atherogenic index did not differ between breeds, but tended to decrease (p < .1) with an increase in dietary energy content. The essential amino acid (EAA) content and ratio of EAA:NEAA (non-essential amino acid) were close to the world standards for healthy meat. In summary, (a) Tibetan sheep meat was preferable to Small-tailed Han sheep meat, although differences between breeds were small; and (b) some carcass parameters and meat quality were improved with an increase in dietary energy level when a low-protein diet was offered.