Saheb Foroutanifar

The effects of dietary zinc (Zn) supplementation on lambs fed diets without added Zn remain controversial, and the precise nature and extent of the associations between Zn administration and lamb responses are not fully understood. To address this, a comprehensive systematic review and dose–response meta-analysis was conducted to explore the effects of Zn supplementation on growth performance, mineral metabolism, and nutrient digestibility. Initially, 3169 studies were identified through comprehensive database searches using relevant keywords. Following a two-stage screening process, 30 eligible articles were selected based on predefined criteria and used in the current meta-analysis. The one-stage random-effects model was utilized in this meta-analysis, with sensitivity analyses conducted to evaluate the robustness of the derived effect sizes. The results showed nonlinear relationships between Zn supplementation and performance parameters. Optimal Zn levels were identified: approximately 28.51 mg/kg DM for maximum dry matter intake, 37.84 mg/kg DM for highest weight gain, and 42.00 mg/kg DM for best feed conversion ratio. Linear increases in fecal and urinary Zn, and a decrease in apparent Zn absorption, were observed with increasing Zn supplementation (P < 0.05). Zinc supplementation up to 53 mg/kg DM enhanced Zn retention, and up to 107 mg/kg DM, increased liver Zn concentration, with the highest concentration at 50.59 mg/kg DM. Zinc supplementation also affected copper and iron concentrations in various tissues. Specifically, it decreased pancreatic copper up to 22 mg/kg DM but increased it above 50 mg/kg DM. In kidney tissue, copper concentration increased linearly with Zn supplementation from 76 to 150 mg/kg DM, while in liver tissue, it decreased from 42 to 150 mg/kg DM. Heart tissue iron concentration increased up to 24 mg/kg DM but decreased from 41 to 150 mg/kg DM, with the highest concentration at 16.31 mg/kg DM. Zinc supplementation at 28.28 and 20.88 mg/kg DM increased total concentration of rumen volatile fatty acids and dry matter digestibility, respectively. However, final weight, carcass weight, nitrogen metabolism, Zn levels in heart, pancreas, and kidney tissues, copper levels in heart tissue, iron levels in pancreas and liver tissues, and the digestibility of most dietary fractions (organic matter, crude protein, NDF, and ADF) were not affected (P > 0.05). In summary, the findings of this meta-analysis generally align with NRC guidelines; this study underscores the necessity of precise Zn supplementation to optimize lamb productivity and mitigate potential adverse effects.

Background: The study of growth traits is of interest to many animal scientists, regardless of specialization, due to the economic importance of growth rate, mature weight and other related traits. Objective: This study aimed to compare six non‐linear models for describing the growth of Lori‐Bakhtiari sheep. Methods: In order to collect weight data, 85 lambs (41 males and 44 females) were reared from birth to 140 days of age, and their growth patterns were recorded by measuring their body weight at 10‐day intervals. Various mathematical functions, including the negative exponential, Brody, Gompertz, Logistic, Morgan–Mercer–Flodin (MMF) and Weibull, were used to model the relationship between body weight records and age. Results: The results showed that the MMF and Gompertz models provided the best fit to the body weight data, whereas the negative exponential model exhibited the worst fit. In all models, the asymptotic weight of male lambs was higher than females. The research also revealed differences in growth patterns between male and female lambs. Overall, females had a lower absolute growth rate than males, but they reached their peak growth at an earlier period, and their growth rate declined faster. Conclusions: The differences in growth patterns between males and females indicate the importance of analysing male and female data separately when describing growth. As a result, Gompertz model can be recommended to Lori‐Bakhtiari female and male lamb breeders to determine more accurate growth traits. In addition, it should be considered that feeding male and female lambs separately according to absolute growth rate values may increase growth performance.

The poultry's immune system is regulated by various genes involved in both innate and acquired immune responses. Understanding the changes in gene expression post-infection is essential for developing effective intervention strategies and improving disease management in the poultry industry. This study aimed to employ RNA-Seq to investigate the differential gene expression profiles and to identify the essential genes and pathways involved in the host response of poultry infected with the avian leukosis virus. For this purpose, RNA-Seq data of healthy and avian leukosis virus-infected birds on days 24 (n=6) and 40 (n=6) post-infection were used. After quality control and preprocessing, we aligned the reads to the chicken reference genome using STAR software and quantified gene expression using HTSeq-Count. Differential gene expression analysis was performed using the edgeR package in R. The results of this study showed that the uniquely mapped read percentage ranged from 78.07% to 87.74%, and the mismatch rate per base was found to vary between 0.77% and 1.45%. A total of 2,213 and 1165 genes exhibited significant differential expression compared to the control group on day 24 and 40 post-infection, respectively (p<0.05). The gene ontology enrichment and pathway analysis revealed that six candidate genes, AvBD1, AvBD6, CATH1, CATH2, CATH3, and DEFB4A, are associated with the immune response on days 24 and 40. Additionally, on day 24, two more candidate genes, AvBD5 and LYG2, were found to be involved in the immune response.

This study aimed to investigate the association between polymorphisms of ND1 and CYTB genes and in vitro early embryo development of Sanjabi sheep. Blood and ovarian samples were collected from a local slaughterhouse. The cumulus-oocyte complexes with a diameter greater than 3 mm were aspirated from follicles, and in vitro maturation (IVM) and in vitro culture (IVC) rates of them were recorded. A respective 1200 bp and 980 bp fragments of ND1 and CYTB genes were genotyped using a modified single strand conformation polymorphism (SSCP) method. The results of this study revealed that four different patterns, named as A, B, C, and D were observed for both ND1 and CYTB genes. The ND1 gene polymorphisms had significant effects on the IVM and IVC rate (p < 0.05). The pattern C of the ND1 gene significantly increased the IVM rate compared to the patterns A, B and D. For the IVC, the highest and lowest means were related to the C and B patterns, respectively. The CYTB gene polymorphisms also had significant effects on IVC (p < 0.01), but the IVM did not affected (p = 0.07). Here, the pattern D had the highest and the pattern C had the lowest means for both IVM and IVC rates.

The aim of this study was to investigate mitochondrial ND5 gene polymorphisms and their relationship with in vitro maturation (IVM) and in vitro culture (IVC) of Sanjabi sheep. Blood and ovarian samples of adult ewes were obtained from a local slaughterhouse. For each ovarian sample, cumulus–oocyte complexes larger than 3 mm in diameter were aspirated from follicles, and their IVM and IVC rates were recorded. A 666-bp fragment of the ND5 gene was amplified using the polymerase chain reaction. The samples were genotyped using a modified single-stranded conformation polymorphism (SSCP) method, and an association study was conducted with IVM and IVC rates. Six different SSCP patterns, designated A, B, C, D, E and F with respective frequencies of 8, 47, 4, 4, 32 and 5%, respectively, were observed. According to the results of association analysis, there was no significant association between the ND1 gene polymorphisms and the IVM and IVC rates (P > 0.05).

The present study was conducted to investigate the effects of the activator factor of the WNT pathway, chir98014, leading to the in vitro sheep oocyte maturation medium, on the cumulus cell development, different nuclear maturation stages and the following process of embryonic development. Experiments included (a) addition of different concentrations (0, 0.1, 0.5, 1 µm) of chir98014 to the maturation medium and evaluation of the cumulus cell expansion, (b) addition of different concentrations of chir98014 to the maturation medium and investigation of different nuclear maturation stages, (c) addition of different concentrations of chir98014 to the maturation medium and examination of the subsequent embryonic maturation process and (d) addition of different concentrations of chir98014 to the embryonic development culture medium (the first 48 hr) and investigation of the subsequent embryonic development process. The extracted data were analysed using the SPSS software, considering the significance level of p < .05 and making the mean comparisons. The results showed that the addition of the 0.1 µM concentration of chir98014 to the maturation medium had no significant effects on the oocyte maturation and embryo development post‐fertilization but it enhanced the Cumulus‐oocyte complexes (COCs) expansion. In the fourth experiment, the low concentration of chir98014 in the embryo culture media improved the embryo development process, whereas the high one had a detrimental effect on it, as compared to the control group. Thus, the presence of the lower concentrations of this compound in the embryonic culture medium had favourable effects on the development of embryos.

The main objectives of this study were to compare the prediction accuracy of different Bayesian methods for traits with a wide range of genetic architecture using simulation and real data and to assess the sensitivity of these methods to the violation of their assumptions. For the simulation study, different scenarios were implemented based on two traits with low or high heritability and different numbers of QTL and the distribution of their effects. For real data analysis, a German Holstein dataset for milk fat percentage, milk yield, and somatic cell score was used. The simulation results showed that, with the exception of the Bayes R, the other methods were sensitive to changes in the number of QTLs and distribution of QTL effects. Having a distribution of QTL effects, similar to what different Bayesian methods assume for estimating marker effects, did not improve their prediction accuracy. The Bayes B method gave higher or equal accuracy rather than the rest. The real data analysis showed that similar to scenarios with a large number of QTLs in the simulation, there was no difference between the accuracies of the different methods for any of the traits.