The aim of this study was to analyze potential influences of polymorphisms within the regulatory region of the bovine SIRT6 gene on carcass quality traits. Expression analyses suggested that SIRT6 gene is predominately expressed in kidney, compared with other tissues. In 535 indigenous Chinese beef cattle, two novel single nucleotide polymorphisms (SNPs) were identified within the promoter region of the SIRT6 gene.Association analysis indicated that G allele of the c.-1100 A > G had a positive effect on fat deposition, and the Hap4/4 diplotype had more favourable results than other dipoltypes with respect to the evaluation of carcass quality traits. Furthermore, promoter activity associated with the Hap3 haplotype was measured at higher levels than the Hap1 haplotype, which would be in agreement with the previously described association analysis.The SIRT6 promoter variants significantly affect transcriptional levels and subsequently significantly influence bovine intramscular fat content.
Silent information regulator 1 and 2 (SIRT1, 2) were NAD+-dependent histone or non-histone deacetylase, which emerged as key metabolic sensors in several tissues of mammals. In the present study, the search for polymorphisms within the ovine SIRT1 and SIRT2 loci as well as association analyses between SNPs and growth-related traits were performed in Tibetan sheep. To determine the expression pattern of SIRT1 and SIRT2 genes in Tibetan sheep, the quantitative real-time polymerase chain reaction (qPCR) analysis revealed that those two genes were widely expressed in diverse tissues. Expression of SIRT1 was less in abomasum of lamb, whereas it was greater in duodenum within adult stage. In the case of SIRT2, the greatest expression was observed in reticulum (lamb) and in muscle (adult), whereas the least expression was in liver for lamb and in kidney for adult animals. The association analysis demonstrated that g.3148 C > T polymorphism of SIRT1 affected heart girth (p = 0.002). The g.8074 T > A SNP of SIRT2 had a significant correlation with body weight (p = 0.011) and body length (p = 0.008). These findings suggested that the SIRT1 and SIRT2 polymorphism was involved in growth-related traits in Tibetan sheep, which may be considered to be genetic markers for improving the growth traits of Tibetan sheep.
Abstract Mineral deficient cattle that enter a feedlot have been documented to have increased morbidity and mortality rates and decreased feedlot performance. The objective of this research was to explore current practices used by feedlot producers when receiving mineral deficient cattle. To accomplish this, forty steers were blocked by weight and mineral status, then assigned to one of four treatment groups: control (Con; n = 10), industry mineral requirements (IND; n = 10) top dressed on TMR fed, 2X industry mineral requirements (2XIND; n = 10) top dressed on TMR fed, and MultiMin® injection at labeled dose (MM; n = 10). All steers received the same ration in pens equipped with GrowSafe® bunks. Standing liver biopsies were collected on day 0, 5, 10, 20, 30 and 40 and analyzed for mineral content. Steers were weighed on day 0, 14, 28, 41, 56, 70, 84, and 110. Average daily gain (ADG), dry matter intake (DMI) and feed efficiency (FE) were recorded. After the trial, steers were harvested at a commercial facility and carcass data was obtained from the plant. There were no differences (P > 0.05) in weight gain or overall ADG between treatment groups. When analyzed over time, treatment had an effect (P < 0.001) on liver copper and selenium concentrations, but no effects (P > 0.05) were observed on liver manganese and zinc concentrations. Additionally, when DMI was analyzed over time, effects (P < 0.05) of time, treatment, and treatment*time were observed, and effects (P < 0.05) of time and treatment*time were observed on FE. Treatment had no effect (P > 0.05) on carcass data. These data indicate that different mineral supplementation strategies have diverse effects on feedlot performance and liver mineral concentrations over time.
Abstract This research compared the use of implants in Bos indicus influenced animals versus Bos taurus in a feedlot setting. Twenty steers were blocked by weight and breed in a 2 x 2 factorial design examining two different breeds: Angus (AN; n = 10) or Santa Gertrudis influenced (SGI; n = 10), and two implant strategies: no implant (CON; n = 10) or a combined implant (CI; n = 10). Steers were randomly placed into pens equipped with GrowSafe® bunks, fed the same ration, and weighed and ultrasounded on days 0, 28, 56, 84, and 112. Blood was collected on days 0, 2, 10, 28, 56, 84, and 112. Backfat measurements (BF), weights, and blood urea nitrogen (BUN) were determined. Data were analyzed using repeated measures and the ProcMixed procedure of SAS, looking at the main effects of breed, implant, and breed*implant. There were no initial differences (P > 0.05) in weight between any of the main effects. The main effects of breed, implant, and breed*implant demonstrate that AN gained more (P < 0.05) weight than SGI, CI gained more (P < 0.05) weight than CON, and the AN that received a CI had increased weight gain when compared to the AN CON, SGI CON and SGI CI. There was no difference (P > 0.05) in weight gain between the SGI that received a CI vs CON, nor was there a difference (P > 0.05) between the CON SGI and AN. There was a treatment*breed interaction for BF (P < 0.05), with AN tending to put on more BF than SGI CON (P < 0.08). A breed*treatment interaction was also observed when analyzing BUN (P < 0.05). This research provides preliminary evidence suggesting that anabolic implants are not as effective in Bos indicus influenced animals when compared to Bos taurus animals.
Abstract Grazing lands in the western US are deficient in several trace minerals known to be critical for livestock health and performance. Mineral supplementation is often not possible since animals graze rough terrain, making mineral delivery logistically difficult. Therefore, trace minerals are often supplemented during the growing and feedlot period to maximize cattle health and production. However, morbidity and mortality rates are often greater in these mineral deficient cattle, at least in part due to their mineral deficiencies, and producers welcome input on best practices for mineral supplementation. This study aimed to evaluate how different mineral supplementation strategies affect liver mineral concentrations and abundance of mRNA involved in mineral transport in mineral deficient cattle receiving different mineral supplementation strategies. Sixty mineral deficient feedlot steers were obtained and initially stratified by weight into one of four treatment groups (n = 15): no mineral supplementation (CON); dietary mineral supplementations at industry recommended levels (DM); multimin injection at labeled dose (MM); or a combination of the MM and DM treatments (MM+DM). Treatments were given for the first 40 days of the trial and steers were fed ad libitum in pens equipped with GrowSafe bunks. Liver biopsies were conducted on days 0, 5, 10, 20, 30 and 40 to assess liver mineral concentrations of copper (Cu), manganese (Mn), selenium (Se), and zinc (Zn). Total mRNA was isolated from liver biopsies on days 0, 20, and 40 and mRNA abundance of genes involved in trace mineral transport was measured. The liver mineral data was analyzed using the PROC MIXED procedure of SAS with day as a repeated measure to evaluate the fixed effect of treatment. A series of contrasts were also conducted to determine whether mRNA abundance differed between the mineral treatments and the CON. There was a treatmentxday interaction (P < 0.05) on the Cu concentration where the MM treatment peaked at day 20 and then started to decrease towards day 40. All mineral treatments increased (P < 0.05) the liver Se concentration and mRNA abundance of zinc transporter (ZNT) 7, ZNT9, and Mn superoxide dismutase (MnSOD) compared with the CON. Steers receiving the DM treatment increased (P < 0.05) the mRNA abundance of Zrt- and Irt-like proteins (ZIP) 1, ZNT1, ZNT3, and ZNT4 compared with the CON. When compared with the CON treatment, the DM and MM+DM had a tendency (P = 0.07) to increase the abundance of divalent metal transporter 1 (DMT1) and ZNT1, as well as the liver Mn concentration. Overall, both the MM+DM and DM treatments improved mineral status by increasing liver mineral concentrations. However, the DM treatment was more effective at increasing the mRNA abundance of mineral transporters in the liver. Further research is needed to determine which pathways were influenced by an improved trace mineral status.
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