Small Ruminant Research最新文献

The growth rate of sheep determines their productivity; the faster the growth rate, the higher the productivity. Sheep growth is usually measured by body weight, which is an important indicator of overall growth, and body size, which reflects body shape and structure. Therefore, in sheep production, the selection and improvement of growth traits is one of the important means to improve production efficiency. In this study, 857 males of Hu sheep were selected to record growth traits, including body weight, height, length, and chest, and cannon circumference at 80, 100, 120, 140, 160 and 180 days of age, as well as live weight before slaughter and carcass weight. Correlation analyses conducted between these growth traits at different stages were significantly correlated with both live weight before slaughter and carcass weight. And the strongest correlation was observed for body weight, while body height showed the weakest correlation. The myosin heavy chain 3 (MYH3) gene in the MYH gene family was selected as the target gene, and a synonymous mutation (MYH3 g.33834192A>G) in the exon 12 region of MYH3 was identified by polymerase chain reaction (PCR) and Sanger sequencing. Further association analysis using competitive allele-specific PCR (KASPar) technique showed that the MYH3 g.33834192A>G locus was significantly (P < 0.05) associated with growth traits (including body weight from 80 to 160 days of age, body height at 80 and 100 days of age, body length at 100 and 140 days of age, chest circumference at 80, 100, 160, and 180 days of age, cannon circumference at 80–140 days of age and carcass weight). Among them, the dominant genotype was GG. Meanwhile, the tissue expression results indicated that the highest level of MYH3 gene expression was found in muscle tissues. Therefore, this locus can be used as a candidate molecular genetic marker for improving growth traits in Hu sheep.

Variation in feed resource availability within production systems can cause genotype by environment interactions that change the ranking of the best animals to select between environments. Mediterranean environments have high variation in pasture growth between years that could cause genetic by environment interactions for sheep production traits. Therefore, we estimated heritabilities for live weight, fleece weight, fibre diameter and number of lambs weaned in six years from 2000 to 2005 and correlations between years comparing multivariate analysis and random regression analysis. We compared 3 methods: 1 multivariate analysis estimating (co)variances for traits in each year, 2 Random regression estimated (co)variances for intercept and slope for traits as repeated measurements fitted against average pasture growth in each year and 3. Random regression fitted against corrected average performance of animals in each year. Random regression was estimated with an order of polynomial of one for additive genetic variance and zero for permanent environmental effects. This combination of polynomials was the best fit based on Bayesian information criterion. We estimated heritabilities for each year and correlations between years using records from 3299 pedigreed Merino ewes managed at Katanning in Western Australia. There were 4651 records for adult live weight, 6750 for adult clean fleece weight, 6965 for adult fibre diameter, and 7774 for number of lambs weaned across all 6 years. Number of lambs weaned had more genotype by environment interactions than other traits, with fibre diameter and fleece weight having genotype by environment interactions between only a few years. Based on Bayesian information criterion values, multivariate analysis fit the data better for live weight, fleece weight and fibre diameter. Additionally, random regression estimated higher genetic correlations between years than multivariate analysis suggesting there was not enough flexibility in the random regression analysis, which used only first order polynomials, to fit differences between years. Pasture growth across years did not explain differences in performance for traits across years. Therefore, for number of lambs weaned, random regression using corrected average performance was a better fit than average pasture growth. For other traits, more years or a better indicator of variation in performance within and between years are required to use random regression for genotype by environment interactions.

Oxalic acid, a crucial secondary metabolite prevalent in most plants, often constitutes an unavoidable component of the diet for grazing animals, particularly in saline-alkaline grasslands. This research focused on examining the effects of elevated oxalic acid consumption on various aspects of sheep health and metabolism, including growth performance, nutrient digestibility, blood biochemical indices, rumen fermentation, and microbial populations. Employing a single-factor experimental model, 24 six-month-old German Merino sheep (with an average body weight of 32.08 ± 3.43 kg) were systematically segregated into three distinct groups. Each group contained eight replicates, with each replicate comprising a single sheep. The diet of the experimental groups was enhanced with oxalic acid concentrations of 1 % (T1) and 2 % (T2), whereas the control group received no oxalic acid addition. Under ad libitum feeding, the duration of the experimental phase spanned a total of 60 days. Outcomes demonstrated that a 2 % oxalic acid augmentation notably diminished the sheep's daily weight gain (ADG) (P<0.05), elevated the feed conversion ratio (FCR) (P<0.05), and reduced the ruminal pH levels (P<0.05), compared to both control group and 1 % oxalic acid group. This pH reduction markedly curtailed the synthesis of essential ruminal constituents such as acetic acid, propionic acid, and butyric acid (P<0.05). Furthermore, there was a notable decline in serum alkaline phosphatase (ALP) levels, alongside rises in both blood urea nitrogen (BUN) and serum creatinine (CREA)(P<0.05), coupled with a significant reduction in serum calcium concentrations (P<0.05) in 2 % oxalic acid group, compared to both control group and 1 % oxalic acid group. Moreover, the 2 % oxalic acid addition adversely impacted the digestibility of neutral detergent fibre (NDF) and acid detergent fibre (ADF), as well as the concentration of NH₃-N in the rumen fluid (P<0.05), compared to both control group and 1 % oxalic acid group. Pertaining to rumen microorganisms, there was a significant escalation in the relative abundance of Proteobacteria at the phylum level, contrasted by a substantial reduction in the presence of Fibrobacteres (P<0.05). At the genus level, an increased concentration of oxalic acid in the diet correlated with a pronounced decline in the relative abundance of Prevotella_1, and a substantial decrease was observed in the relative abundance of Ruminococcaceae_UCG-014 (P<0.05). In summary, while sheep can acclimate to an inclusion of 1 % oxalic acid in their diet, an augmentation of 2 % oxalic acid appears detrimental, impinging upon growth performance, fiber and crude protein (CP) digestibility, blood calcium levels, rumen pH, volatile acid content, and the microbial ecosystem within the sheep’s rumen.

This experiment was conducted to evaluate the effect of milk thistle (Silybum marianum) seed powder supplementation in the diet on weight gain, feed conversion efficiency, and physiological parameters in fattening lambs. In this experiment, thirty crossbred Shawl × Romanov male lambs were divided into three groups based on a completely randomized design. The experimental treatments included a control group receiving a diet without milk thistle seed powder (MSP), a group receiving a diet containing 1 % MSP, and a group receiving a diet containing 2 % MSP. Animals fed the diet containing 2 % MSP exhibited higher nutrient intake, average daily gain, and final body weight compared to the other treatment groups (P < 0.05). Lambs receiving the 2 % MSP diet had the most favorable feed conversion ratio (P < 0.05). The apparent digestibility of dry matter, organic matter, and crude protein was highest in lambs fed the diet containing MSP compared to the control group (P < 0.05). Ruminal NH₃-N concentration and populations of total protozoa and Entodinium genus were lowest in lambs fed the MSP-containing diets (P < 0.05). The molar concentrations of acetate and valerate in the rumen fluid of lambs receiving the diet containing 2 % MSP were lower compared to the control group, while propionate concentration was higher (P < 0.05). Feeding the diet containing 2 % MSP reduced serum cholesterol, triglycerides, LDL, and liver enzyme activities compared to the control group (P < 0.05). Based on these results, supplementing lamb diets with 2 % MSP increased growth performance measures, nutrient digestibility coefficients, and reduced blood cholesterol and LDL concentrations.

In ruminants, the signal (interferon-tau, IFNT) for the maternal recognition of pregnancy has effects on maternal extrauterine organs, and progesterone plays a key role during pregnancy. However, it is unclear that early pregnancy has effects on the expression of interferon-stimulated genes (ISGs), progesterone receptors (PGRs), and progesterone-induced blocking factor (PIBF) in ovine small intestine. In this study, small intestines were obtained at day 16 of the estrous cycle, days 13, 16, and 25 of pregnancy, and RT-qPCR assay, Western blot, and immunohistochemistry were used to analyze the effects of early pregnancy on the expression of ISGs, PGR, and PIBF in the small intestine. The results indicated that expression levels of ISG15-conjugated protein, signal transducer and activator of transcription 1 (STAT1), myxovirus resistance protein 1, and interferon-gamma-inducible protein 10 (IP-10) at day 13 of pregnancy were the lowest. However, expression levels of PGR isoforms (60 kDa and 40 kDa), PIBF, STAT1 and 2′,5′-oligoadenylate synthetase 1 upregulated, but the expression value of IP-10 downregulated at day 25 of pregnancy compared with day 16 of the estrous cycle. In conclusion, early pregnancy modulated the expression of ISGs, PGR, and PIBF in ovine duodenum, which was implicated in immunoregulation and nutrient absorption of the small intestine in ewes.

The objective of the research was to quantify the levels of heat stress, physiological variables and losses of sensible and latent heat in sheep native to the Brazilian semi-arid region, kept in a climatic chamber at thermoneutral temperatures and heat stress. The experimental design was completely randomized with five temperatures and 24 sheep, with an average age of 5.0±1.0 months and an average weight of 15.0±2.3 kg. According to the heat stress index (HSI) at temperatures from 20.0 to 28.0 °C the environment was classified as comfortable, at a temperature of 32.0 °C, the environment was classified as mild to moderate discomfort, and at a temperature of 36.0 °C, it was classified as alert. With the increase in temperature, the animals significantly (P<0.05) increased rectal and superficial temperatures and respiratory rate and, in TNT, sensitive heat exchanges corresponded to an average of 55.9 % and in HST to 12.9 % of the total, and at a temperature of 32.0 °C, sensible heat exchanges corresponded to 17.9 % and latent heat exchanges corresponded to 82.1 % and, at a temperature of 36.0 °C, 95.8 % of heat exchanges were due to latent means, of which 85.1 % were cutaneous. Sheep kept in stressful thermal conditions increase their physiological variables and eliminate the majority of excess metabolic heat through latent means (skin and respiratory tract).

Lipoprotein lipase (LPL) is regarded as a candidate gene to regulate fatty acid (FA) composition. The study examined the mRNA expression levels of LPL in different tissues, and conducted a genetic association between the FA composition of the longissimus dorsi muscle of 1029 Hu sheep and the single nucleotide polymorphisms (SNPs) in the LPL gene, as well as the combined genotypes and haplotypes. The results showed that LPL had the highest expression levels in tail fat and subcutaneous fat. Eight SNPs were identified and successfully typed in the intronic region of the LPL gene. Correlation analysis showed that all eight SNPs were related to FA composition. Among them, the CC genotype of SNP1 (g.13879 T>C), the AA genotype of SNP2 (g.13971 A>G), and the TT genotype of SNP3 (g.13993 T>A) had the lowest levels of C8:0 and the highest levels of C18:3n3 content. The TT genotype of SNP6 (g.23413 T>C) and SNP7 (g.23469 T>C) and the AA genotype of SNP8 (g.23472 T>A) had the highest levels of C20:1 content. Linkage disequilibrium analysis showed that SNP1, SNP2, and SNP3 were located in block1, SNP4 (g.17118 A>G) and SNP5 (g.17188 A>G) were located in block2, and SNP6, SNP7, and SNP8 were located in block3. The C18:2n6c content of the TTAAAA combined genotypes in Block1 and the GGGG combined genotypes in Block2 was significantly higher than other combined genotypes. Haplotypes in both Block1 and Block2 significantly affected C18:0, C20:1, and C18:3n3. In conclusion, these genetic markers provide an important source of variation for the selection of FA composition of sheep muscle, which can accelerate the sheep breeding of high-quality meat with a balanced distribution of FA composition.

This study was performed to evaluate the effects of replacing ground corn with Parkia platycephala pods (PPs) in lamb diets on the physicochemical characteristics of meat, the fatty acid profile in meat, and ruminal biohydrogenation (RBH). Twenty-eight castrated male lambs (20.05 ± 0.44 kg, 120 ± 10 days old) were distributed in a randomized block design constituting four treatments and seven replications. Four diets were formulated by replacing ground corn with PPs at increasing levels: 0 % PPs and 100 % ground corn (299.4 g/kg dry matter [DM]), 33 % substitution of ground corn (199.5 g/kg DM) with PPs (100.3 g/kg DM), 66 % substitution of ground corn (99.7 g/kg DM) with PPs (200.5 g/kg DM), and 100 % PPs (300.6 g/kg DM) and 0 % ground corn. The PPs resulted in a reduction in C18:1c9 intake; increased C12:0, C15:0, C18:1t9, C18:1t11, and C18:2n6; and reduced C18:0 in ruminal digesta, with a quadratic effect for C4:0 (P < 0.05). The RBH rate of C18:1c9 and C18:2n6 (P < 0.05) decreased as the PP levels in the diets increased. Regarding fatty acids in meat, there was a reduction in C16:1c9, C18:1c9, and cis-monounsaturated fatty acids and a quadratic effect for C14:1c9 and C18:2c9t11 (P < 0.05) as the PP levels in the diets increased. Levels of 66 % and 100 % PPs in the diets provided higher C18:2n6 in meat compared with the control diet (0 % PPs) and the diet containing 33 % PPs (P < 0.05). Under these experimental conditions, the replacement of corn with PPs in diets for lambs changed the fatty acid profile in the rumen digesta and lamb meat, promoting an increase in C18:1t11 in the rumen digesta. PPs can be used as an alternative ingredient in lamb feeding because they provide nutritional characteristics similar to those provided by corn.

Aquaporins (AQP) are transmembrane proteins that function as channels for water molecules' movement. It is conserved across bacteria, plants and animals. It helps in thermoregulation during extreme climatic conditions. So, this study focuses on the expression of AQP1, AQP2 and AQP3 in the ureter and bladder tissues of goat (Capra hircus) during winter, spring and summer seasons. The study was conducted on goats (n=30) to investigate the expression of AQP (water channels) in ureter and urinary bladder and metabolic and hormonal influence by aquaporins. mRNAs were isolated from ureter and urinary bladder tissues and cDNA were synthesized for RT-PCR expression studies. Biochemical parameters were studied in the blood samples. AQP1 mRNA expression was non-significant in goat ureters but considerably greater (p<0.05) in the urine bladder during summer compared to winter. During the summer, both ureter and urinary bladder tissue samples showed increased expression of AQP2 and AQP3. Aquaporins 3 had significantly greater (p<0.05) mRNA expression in the ureter and urine bladder than Aquaporins 1 and 2 throughout the summer season. The significant (p<0.05) increase in physiological responses, haematological counts and blood biochemical components seen in goats throughout the summer season. Finally, it concludes that AQP and their role in thermotolerance and direct association with effective water balance mechanisms in the body via expression of AQP in different extreme climatic conditions.

The aim of the present experiment was to evaluate the partial or complete replacement of cotton seed meal (CSM) with fenugreek seed meal (FSM) on chemical composition, in vitro ruminal fermentation, the growth performance and economic efficiency of growing lambs. Thirty-two male Ossimi lambs weighing 42±0.7 kg, and 210±7 d were divided randomly into four experimental groups of eight lambs each. Lambs were fed four diets containing 40 % berseem clover and 60 % concentrate feed mixture. Cotton seed meal was replaced with FSM at 0 % (FSM0; control treatment), 50 % (FSM50 treatment), 75 % (FSM75 treatment) or 100 % (FSM100 treatment). The experiment was lasted for 105 d consisting of 15 d for adaptation and 90 days for measurements. The replacement did not affect crude protein (CP) or gross energy (GE) of the diets. However, the concentrations of individual amino acids and polyphenols differed between CSM and FSM. Diets containing FSM reduced the in vitro methane production (P=0.024) by 30–41.1 %, and nutrient degradability (P<0.05). The highest DM intake was observed (quadratic effect, P<0.001) with lambs fed the FSM50 diet (1.68 kg DM), which also showed the highest final body weight (65.5 kg) (quadratic effect, P=0.045), total weight gain (22.6 kg) (quadratic effect, P=0.034), and daily weight gain (251.1 g) (quadratic effect, P=0.033). Higher organic matter digestibility (∼ 69.4 %) was observed (quadratic effect, P=0.016) with the lambs of FSM50 treatment (P<0.05). Replacing CSM with FSM linearly increased (P=0.024) blood antioxidant activity and decreased blood cholesterol (P=0.022), triglycerides (P=0.035) and high-density lipoprotein (P=0.034) compared to the control treatment. The highest relative percentage of net revenue was observed with the FSM50 diet (131 %) while the lowest one was observed (P=0.011) with the FSM100 diet (92.9 %). It is concluded that CSM can be replaced with FSM at 50 % in diets of growing lambs for better performance and economic efficiency.