Iranian Sheep Breeds Research Articles

Association of the calpastatin genotypes, haplotypes, and SNPs with meat quality and fatty acid composition in two Iranian fat- and thin-tailed sheep breeds

This study was conducted to investigate the relationship between variation within Calpastatin (CAST) gene and meat quality and fatty acid profiles in fat-tailed (Chall) and thin-tailed (Zel) Iranian sheep breeds using PCR–SSCP, DNA sequence, and genotype, haplotype, and SNP effect analyses. Six previously identified SNPs including C24T, G62A, G65T, and T69- located in intron 5 and c.197A>T and c.282G>T localized in exon 6 were observed. These SNPs constituted six haplotypes of CAST-1, CAST-2, CAST-6, CAST-8, CAST-10, and CAST-11, corresponding to six genotypes of “B”, “C”, “D”, “F”, “I”, and “J”. Animals inheriting genotype “I” had lower value of shear force (P<0.03), concentration of palmitic acid (P<0.05), cholesterol (P<0.05), and n−6:n−3 ratio (P<0.02), and higher content of palmitoleic acid (P<0.04) compared to those inheriting the other genotypes. Also, animals containing one copy of CAST-10 haplotype showed lower value of shear force (P<0.005), lower n−6:n−3 ratio (P<0.02), higher concentration of palmitoleic acid (P<0.04) and total mono-unsaturated fatty acid (P<0.02) than those containing the other haplotypes. SNP effect analyses showed that three SNPs including G62A, G65T, and c.197A>T had significant effects on the content of some fatty acids and their selected ratios (P<0.05 to P<0.001), shear force (P=0.006 and P<0.001), and the cholesterol content of longissimus dorsi muscle (P<0.05). Overall, it seems that genotype “I”, haplotype CAST-10, the “AA” genotype of SNP G62A, and the “GT” genotype of G65T SNP were the most desirable genotypes and haplotype when selecting lambs in terms of both tenderness and fatty acid composition of meat, because selecting these genotypes and this haplotype would increase tenderness and proportion of healthy fatty acids, and also decrease proportion of harmful fatty acids of meat.

P5050 A genome-wide scan for signature of positive selection in some Iranian sheep breeds

The sheep is the earliest grazing animals to be domesticated that produces a great scale of animal-based protein for human consumption and plays an essential role in the modern agricultural economy. Iran is one of the important centers for sheep genetic resources and breeding in the world. The aim of the present study was to investigate the selective sweeps between three Iranian sheep breeds, namely Baluchi, Lori-Bakhtiari and Zel using the Illumina ovine SNP50k BeadChip. The Weir and Cockerham’s FST (Theta) method was applied to detect the selection sweeps across the genome. In total, thirty eight genomic regions were identified on 1, 2, 3, 4, 5, 7, 8, 10, 11, 12, 13, 15, 16, 18 and X chromosomes with high population differentiation between different Iranian sheep breed comparisons. Study of the genes has already been reported in these regions and revealed that almost all of these loci are associated with the genes involved in reproduction traits, cytology cells and nervous system, immune system, muscular system, sugar and energy metabolism. Our results reported genomic scans for selective sweeps in Iranian sheep breeds and could help detect functional candidate genes under positive selection and also better understand the relationship between genomic composition and phenotypic diversity for further genetic and breeding research in Iranian sheep breeds.

P5050 A genome-wide scan for signature of positive selection in some Iranian sheep breeds

P5050 A genome-wide scan for signature of positive selection in some Iranian sheep breeds

Polymorphism in the SCD gene is associated with meat quality and fatty acid composition in Iranian fat- and thin-tailed sheep breeds

The enzyme stearoyl-coenzyme A-desaturase (SCD) has been proposed as a key regulator for fat content and fatty acid composition of meat. In this study, a DNA sequence and single-strand confirmation polymorphism analysis were performed in an attempt to investigate the relationship between variation within the SCD gene and fatty acid profiles, physicochemical composition, and the quality characteristics of longissimus dorsi (LD) muscle in two traditional fat- (Chall) and thin- (Zel) tailed Iranian sheep breeds. Only one previously reported SNP (g.379A>T) located in the 5′ untranslated region of the SCD gene was observed. Two previously reported allelic variants, SCD-1 and SCD-2, constituted two previously reported genotypes, “A” and “B”. Based on t-test, no allelic and genotypic frequency differences were observed between Chall and Zel breeds. Lambs with genotype “B” significantly had lower total saturated fatty acid (SFA) level (p<0.05) and more linoleic (p<0.02), arachidonic (p<0.002), and eicosapentaenoic (EPA) (p<0.001) acids and total poly-unsaturated fatty acid (PUFA) (p=0.002) contents and PUFA: SFA ratio (p<0.004) than those with genotype “A”. Meat color of the genotype “B” lambs was lower for a* (p<0.05) and higher for L* (p<0.08) compared to the genotype “A” ones. There were some interactions between breed and SCD gene in terms of palmitic acid (p<0.04), cooking loss (p<0.05), and protein content (p<0.03) of LD muscle. SCD locus explained 17.3%, 15.3%, 13%, and 12% of the phenotypic variation in terms of EPA and arachidonic acid, and PUFA contents and PUFA: SFA ratio, respectively. Interestingly, the results of the correlation analyses showed the significant negative correlations between healthy fatty acid indices (PUFA and PUFA: SFA) and meat color measures of a* and b* (r=−0.26 to r=−0.40, p<0.05) and the significant positive correlations between n–6: n–3 PUFA, one of the main harmful fatty acid indices, and a* (r=0.41, p<0.01) and b* (r=0.27, p<0.05) values which are coordinated with the effect of SCD genotypes on fatty acid composition and color of meat. So, both fatty acid composition and meat color traits should be considered in marker-assisted selection based on SCD gene. Overall, it seems that the genotype “B” of SCD gene is a more desirable genotype when selecting lambs in terms of both fatty acid composition and color of meat, because selecting this genotype would result in higher proportion of healthy fatty acids, lower proportion of harmful fatty acids, and better meat color.

Erratum to: Associations of POU1F1 gene polymorphisms and protein structure changes with growth traits and blood metabolites in two Iranian sheep breeds

Erratum to: Associations of POU1F1 gene polymorphisms and protein structure changes with growth traits and blood metabolites in two Iranian sheep breeds

Patterns of milk production, blood metabolite profile and enzyme activities of two fat-tailed sheep breeds

This study was conducted to compare milk yield and composition, blood parameters and enzyme activities between two fat-tailed Iranian breeds of sheep (Mehraban and Sanjabi). Two groups of eight ewes per breed were kept indoors and fed a diet based on alfalfa hay (60%) and concentrates (40%). Milk production of the individual ewes was measured and sampled weekly for 11 weeks and blood samples were obtained at 28, 56 and 77 days of lactation. No significant differences between the breeds were evident in average daily milk production and fat and lactose contents, but average milk protein content tended to be higher (P = 0.05) in Mehraban than in Sanjabi ewes. However, milk and protein yields were higher (P &lt; 0.05) in Mehraban ewes in the last two-thirds of lactation. Plasma lipid profile (triglyceride, cholesterol, HDL- and LDL-cholesterol) was not different between the two breeds at any time of study. At the end of lactation, plasma urea contents and alanine amino transferase activities were higher (P &lt; 0.05) either before or after feeding in Mehraban than in Sanjabi ewes, which suggests a more intense metabolic activity in the former probably related to their higher milk and protein production at that stage of lactation.

Erratum to: Associations of POU1F1 gene polymorphisms and protein structure changes with growth traits and blood metabolites in two Iranian sheep breeds

Erratum to: Associations of POU1F1 gene polymorphisms and protein structure changes with growth traits and blood metabolites in two Iranian sheep breeds

Associations of POU1F1 gene polymorphisms and protein structure changes with growth traits and blood metabolites in two Iranian sheep breeds.

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Association of pituitary specific transcription factor-1 (POU1F1) gene polymorphism with growth and biometric traits and blood metabolites in Iranian Zel and Lori-Bakhtiari sheep.

The pituitary-specific positive transcription factor 1 (POU1F1) gene has been the subject of many recent studies because of its important roles in growth and development of mammals. In this study, we investigated the single nucleotide polymorphisms (SNPs) at the third exon of POU1F1 gene and its association with growth and biometric traits and blood metabolites in two Iranian sheep breeds, Zel and Lori-Bakhtiari. Blood samples from 90 Lori-Bakhtiari and 90 Zel sheep were collected to extract DNA and the 295-bp fragment of the POU1F1 gene was amplified and the restriction fragment length polymorphism (RFLP) technique was adopted for genotyping. A SNP was identified in both Lori-Bakhtiari and Zel sheep breeds, which represents a non-synonymous single base mutation at restriction site for endonuclease AciI. The results revealed differential frequencies of alleles between the two studied breeds, where A allele was more frequent in Lori-Bakhtiari breed, while G allele was more frequent in Zel breed. When POU1F1 genotypes were tested, the animals with AA genotype had a higher weaning weight than those with GG genotype (p < 0.05), however there were not significant association between genotypes and birth weight, biometric traits (body length, body height, heart girth, thigh girth and abdominal girth) and blood metabolites (triglyceride and cholesterol) of the studied breeds (p > 0.05). These findings imply that the POU1F1 polymorphism may affect weaning weight, thus can be used as a molecular marker for this production trait.

Detecting novel SNPs and breed-specific haplotypes at calpastatin gene in Iranian fat- and thin-tailed sheep breeds and their effects on protein structure

Calpastatin has been introduced as a potential candidate gene for growth and meat quality traits. In this study, genetic variability was investigated in the exon 6 and its intron boundaries of ovine CAST gene by PCR-SSCP analysis and DNA sequencing. Also a protein sequence and structural analysis were performed to predict the possible impact of amino acid substitutions on physicochemical properties and structure of the CAST protein. A total of 487 animals belonging to four ancient Iranian sheep breeds with different fat metabolisms, Lori-Bakhtiari and Chall (fat-tailed), Zel-Atabay cross-bred (medium fat-tailed) and Zel (thin-tailed), were analyzed. Eight unique SSCP patterns, representing eight different sequences or haplotypes, CAST-1, CAST-2 and CAST-6 to CAST-11, were identified. Haplotypes CAST-1 and CAST-2 were most common with frequency of 0.365 and 0.295. The novel haplotype CAST-8 had considerable frequency in Iranian sheep breeds (0.129). All the consensus sequences showed 98–99%, 94–98%, 92–93% and 82–83% similarity to the published ovine, caprine, bovine and porcine CAST locus sequences, respectively. Sequence analysis revealed four SNPs in intron 5 (C24T, G62A, G65T and T69-) and three SNPs in exon 6 (c.197A>T, c.282G>T and c.296C>G). All three SNPs in exon 6 were missense mutations which would result in p.Gln 66 Leu, p.Glu 94 Asp and p.Pro 99 Arg substitutions, respectively, in CAST protein. All three amino acid substitutions affected the physicochemical properties of ovine CAST protein including hydrophobicity, amphiphilicity and net charge and subsequently might influence its structure and effect on the activity of Ca2+ channels; hence, they might regulate calpain activity and afterwards meat tenderness and growth rate. The Lori-Bakhtiari population showed the highest heterozygosity in the ovine CAST locus (0.802). Frequency difference of haplotypes CAST-10 and CAST-8 between Lori-Bakhtiari (fat-tailed) and Zel (thin-tailed) breeds was highly significant (P<0.001), indicating that these two haplotypes might be breed-specific haplotypes that distinguish between fat-tailed and thin-tailed sheep breeds.

Identifying Novel SNPs and Allelic Sequences of the Stearoyl-CoA Desaturase Gene (SCD) in Fat-Tailed and Thin-Tailed Sheep Breeds

Stearoyl-coenzyme A-desaturase (SCD) is a candidate gene for genetic variation in the fatty acid composition of meat and milk. The SCD enzyme catalyzes a D9-cis desaturation of a number of fatty acyl-CoA substrates with a preference for C16:0 and C18:0, which are converted to C16:1 and C18:1, respectively (Enoch et al. 1976). SCD is also a key enzyme in endogenous production of the cis-9, trans-11 isomer of conjugated linoleic acid (CLA) (Bauman et al. 1999). In sheep, two single nucleotide polymorphisms (SNPs), located in intron 4 (Miari et al. 2009) and intron 2 (GarciaFernandez et al. 2010), displayed significant association with CLA/VA variability and milk fat percentage, respectively. The objective of this study was to determine the existence of polymorphisms in the SCD gene in 458 lambs belonging to three traditional fat-tailed, medium fat-tailed, and thin-tailed Iranian sheep breeds.

Association Between Single Nucleotide Polymorphism in the Ovine DGAT1 Gene and Carcass Traits in Two Iranian Sheep Breeds

The aim of the study was to investigate the single nucleotide polymorphisms (SNPs) at 16–17 exon of DGAT1 gene in Lori-Bakhtiari sheep (LB) and Zel sheep (Z) breeds and provide a foundation for studying the relationship of DGAT1 gene with some carcass traits and the genetic relationship between LB sheep and Z sheep breeds. A total of 309 sheep were slaughtered and the carcass weight, backfat thickness, fat-tail weight, fat-tail percentage, dressing percentage, and dressing percentage adjusted to fat-tail weight were measured. Single nucleotide polymorphism was detected by comparing sequences of PCR products, and the restriction fragment length polymorphism (RFLP) technique was adopted for genotyping. The results of PCR-RFLP analysis showed that the SNP had three genotypes of TT (272 and 37 bp), TC (309, 272, and 37 bp), and CC (309 bp), in which TT was the predominant genotype and allele T was predominant allele in LB and Z sheep breeds. At the DGAT1 locus, CC sheep showed the significantly greater fat-tail weight (P < 0.05) and backfat thickness (P < 0.01). The results of this study demonstrate novel associations in which the C allele had a positive effect on fat-tail weight and backfat thickness in fat-tailed sheep.

Variation in colostral immunoglobulin G concentration in fat tailed sheep and evaluation of methods for estimation of colostral immunoglobulin content

In ruminants, colostrum is a vital source of immunoglobulins that provide passive immunity for their offspring during the neonatal period. It is suggested that colostral immunoglobulin G (IgG) concentration varies between and within breeds and could also be affected by maternal factors. The aim of this study was to investigate possible effects of litter type and ewe parturition number on colostral IgG concentration in two Iranian fat-tailed breeds of sheep (Shaul and Lori Bakhtyari) as well as usefulness of different methods for estimation of IgG concentrations in colostrum. The colostral IgG concentrations were measured in 38 Shaul and 59 Lori Bakhtyari ewes by single radial immunodiffusion, zinc sulphate turbidity and Biuret methods. Measurement of IgG by single radial immunodiffusion revealed that Lori Bakhtyari ewes had significantly (P &lt;0.05) lower colostral IgG levels (48.82 ± 2.10 mg/ml) than Shaul ewes (62.86 ± 2.48). With regard to the effect of litter type and parturition number, a significant (P &lt;0.05) difference in IgG concentration of colostrum was only observed between the first (65.17 ± 5.74 mg/ml) and third parturition (41.10 ± 4.60 mg/ml) of Lori Bakhtyari ewes. The colostral IgG concentration was not associated with ewe serum IgG concentration (P &gt;0.05). The mortality rate was higher in lambs born to ewes with lower IgG in their colostrum. Single radial immunodiffusion did not correlate either with zinc sulphate turbidity method (r = -0.253,P &gt;0.05) or with Biuret method (r = -0.005,P &gt;0.05). We can conclude that concentration of colostral IgG could be influenced by breed but not by litter type and parturition number.

Fiber Quality of Iranian Carpet-Wool Sheep Breeds

This experiment was aimed to identify characteristics and comparative merits of Iranian sheep wool breeds. Fiber characteristics of 75 male and 137 female of 1, 2, 3 and 4 yr of age belonging to Afshari, Zandi, Mehrabani, Lori, and Baluchi sheep breeds were studied. Samples of fiber were taken from the left midside of sheep and analyzed using standard objective measurements for staple length (SL), mean fiber diameter (MFD), coefficient of variation of fiber diameter (FDCV), inner coat fiber ICF, outer coat fiber (OCF), kemp fiber (KF) and yield (Y). A general linear model including sex and age as fixed effects and breed as random effect was used to analyze the data. The mean (and s.e) for SL, MFD, FDCV, ICF, OCF, KF and Y were 110.8±0.1 mm, 36.9±0.5 µm, 50.2%±0.8%, 84.2%±0.6%, 9.8%±0.4%, 5.9%±0.4% and 69.3%±0.7% respectively. MFD of 22% of all wool samples was between 22-30 µm. MFD of a further 36% and 42% of wool samples was between 31-37 µm and coarser than 37 µm. SL of 12% of wool samples was shorter than 100 mm and 38% of samples between 100-120 mm and 50% of samples were longer than 120 mm. There is substantial scope to improve the quality of fiber produced by Iranian sheep breeds through genetic selection.

Comparison of the meat quality and fatty acid composition of traditional fat-tailed (Chall) and tailed (Zel) Iranian sheep breeds

The aim of this study was to compare the meat quality of a traditional fat-tailed breed, Chall, to a tailed Iranian sheep breed, Zel. Lambs were grazed on pasture until weaning, and then were finished until slaughter at 10–12months. Meat quality traits were measured on the longissimus dorsi (LD) muscle. Zel lambs accumulated more intramuscular fat (IMF) (p<0.01) and had lower shear force and drip loss than Chall lambs (p<0.05). The meat color of Zel lambs was higher for both a* (p<0.001) and b* (p<0.01) compared to Chall lambs. Meat from Zel lambs was more tender (p<0.01) and more juicy (p<0.05) than Chall lambs. The PUFA:SFA fatty acid ratio (P:S) was higher (p<0.05) and the n−6:n−3 PUFA ratio was lower in Chall compared to Zel lambs (p<0.05). Overall, these results show that the eating quality of Zel lambs was better, but that this was at the cost of less favorable fatty acid profiles and poorer meat color.

Fattening performance of purebred and crossbred lambs from fat-tailed Kurdi ewes mated to four Iranian native ram breeds

A crossbreeding experiment was carried out to determine the sire breed effects on fattening performance of fat-tailed lambs. Rams from four Iranian fat-tailed sheep breeds, namely Kurdi (K), Afshari (A), Chaal (C) and Sanjabi (S) were mated to Kurdi ewes producing 454 progeny of four genotype groups (KK, AK, CK and SK). A total of 80 lambs comprising ten female and ten male lambs from each genotype group were used in a fattening experiment during a period of 88 days. Genotype of the lamb had significant effect on average dry matter intake (ADMI) (P < 0.05). SK lambs had the lowest ADMI. Average daily gain (ADG) and food conversion ratio (FCR) were not influenced by genotype of the lamb. Sex of the lamb had significant effect on both ADG and FCR (P < 0.01). Slaughter weight (SLW), hot carcass weight (HCW), cold carcass weight (CCW) and daily carcass gain (DCG) were not affected by lamb's genotype. However, genotype had significant effect on dressing percentage, carcass loss percentage (P < 0.01), carcass length (CL), leg circumference (LC), carcass compactness (CC) (P < 0.01) and carcass density (CD) (P < 0.05). Carcass width (CW) and leg length (LL) were not affected by lamb's genotype. Sex of the lamb had significant effects on CL, CW, LC, CC, CD (P < 0.01) and LL (P < 0.05). The results indicated the existence of sire breed difference for daily dry matter intake and carcass conformation in the fat-tailed sheep.

Determination of Wool Follicle Characteristics of Iranian Sheep Breeds

In this study wool follicle characteristics of Iranian sheep breeds were investigated. A total of 242 male and female sheep of different age from 5 breeds were studied. Samples of skin were taken from the right midside to determine follicle characteristics. Overall averages for males and females were 3.7±0.1 and 3.5±0.1 for S/P ratio; 3.2±0.1 and 3.6±0.1 for primary follicle density; 12.1±0.7 and 13.8±0.4 for secondary follicle density; 15.3±0.7 and 17.4±0.4 for total primary plus secondary follicle density; 2.3±0.2 and 3.5±0.3 for percentage of inactive secondary follicles. Significant differences were found in some follicle characteristics between sheep breeds. Results of this study showed that sheep breeds raised in different parts of Iran characterized by a low S/P ratio

Comparison of Carcass Composition of Iranian Fat-tailed Sheep

Most breeds of sheep in Iran are adapted to their agro ecological niches where it is likely that they were also artificially selected by their owners. In general, most of sheep breeds are multipurpose producing lambs, wool and milk. To compare the physical and chemical composition of the carcasses of ten Iranian native fat-tailed sheep breeds, 243 male lambs (6-7 months of age) of ten fat- tailed, Iranian breeds of sheep, Sanjabi (S), Ghezel (G), Afshari (A), Mehrabani (M), Lori (L), Lori Bakhtiari (LB), Kordi Khorasan (K), Sangesari (Sa), Baluchi (B) and Chal (C) were studied. Lamb breed group had a significant (p 0.05) different in the G, A, M and C breeds. The Sa and K breeds showed the lowest lean meat percent. The S lambs showed the lowest (p 0.05). Intramascular fat was significantly (p 0.05) different in S, G, A, M, L and C breeds. M lambs showed the lowest crude protein percentage and S breed the highest (p 0.05) differences among other lamb breeds for this trait. Chemical fat percentage was the same in S, G, A, C and M breeds, but significantly (p 0.05) difference. According to higher lean meat and lower fat percentages in the carcass, the ranking of breeds would be S, G, A, M and C. (Asian-Aust. J. Anim. Sci. 2005. Vol 18, No. 9 : 1348-1352)

Using Linear Body Measurements of Live Sheep to Predict Carcass Characteristics for Two Iranian Fat-tailed Sheep Breeds

Live animal selection programs that favor animals with a minimum amount of carcass fat are used for improving breeding flocks of sheep. To predict carcass characteristics of live sheep using body measurements in breeding flocks, 200 male and female lambs of two fat-tailed Iranian sheep breeds (Moghani and Makui) were used. Depth of soft tissue over the 12th rib of the live animals was measured with ultrasound (ULGR) and with hypodermic needle (NGR). The height at withers (HW), body length (BL), circumference of heart girth (CH) and width of hooks (WH), were measured. All animals were slaughtered; carcasses were cut into joints and dissected. Breed had a significant effect on all of the live measurements. The Moghani breed showed a higher value for HW, CH, ULGR and NGR, compared to that of Makui. Except for soft tissue depths; ULGR, NGR and GR, the male lambs showed higher values in live and carcass measurements than females. Percentages of carcass, total fat and intermuscular fat in females were higher than that of male lambs. In spite of the higher amount of subcutaneous and intermuscular fat in female (which is usually used for their physiological need, such as pregnancy and lactation), the male lambs had a heavier fat-tail than females. There was a wide range of variation of percentage of total carcass fat and total chemical fat content of carcass in the two breeds. Eventually this wide variation could be use by animal breeders for selection of animals with a lesser amount of carcass fat. Live weight of lambs showed a relatively low correlation with percentage of carcass lean, total fat and subcutaneous and intermuscular fat. Total lean meat was predicted with relatively high coefficients of determination in the two breeds (R 2 =0.61 and 0.89, respectively). Live weight and carcass traits were predicted using simple measurements, but with R 2 ranging from 0.53 to 0.93. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 5 : 693-699)

Reproductive Performance of Three Iranian Sheep Breeds

To evaluate the ewe reproductive performances of three Iranian local sheep breeds, namely Moghani, Chal and Zel, 27 rams and 473 ewes were used as the foundation flock in a crossbreeding program. The three breeds were crossed amongst themselves reciprocally. Ram breed and ewe breed showed a two-way interaction on apparent fertility. The Zel ewes showed higher fertility than the Chal and Moghani ewes (94.4 vs 77.3 and 84.6%). Prolificacy among main and individual mating groups were not significantly different (p>0.05). Zel ewes were 22.3 and 14.8% more reproductive (p<0.05) than Chal and Moghani ewes, respectively. Zel and Moghani ewes showed higher (p<0.05) ewe productivity than Chal ewes. Ram breed had a significant (p<0.05) effect on ewe efficiency. The Zel rams were not completely successful to mate with Chal ewes, this caused a to way-interaction between ram and ewe breeds. The Zel ewes mated with Chal and Moghani rams showed 26.1 and 28.5% more efficiency than those mated with Zel rams. This observation strongly supports the use of crossbreeding to improve the efficiency of the Zel ewes. With decreasing lamb mortality, through supplemented feeding of lambs in pre-weaning period, and increasing litter weight, through crossbreeding, it should be possible to improve the efficiency of Zel ewes even better than Chal and Moghani ewes. Small body size of Zel ewes that needs the lower maintenance requirements would be a well advantageous to using Zel ewes as the dam herd to produce commercial lambs in north area of Iran. (Asian-Aust. J. Anim. Sci. 2003. Vol 16, No. 1 : 11-14)