فصلنامه تحقیقات تولیدات دامی
سال یازدهم شماره 2 (تابستان 1401)

Pastures provide an important part of ruminant fodder needs, and farmers store some pasture plants to use in winter-feeding of livestock. Therefore, having enough information about the nutritional value of such plants can help to optimize their consumption in animal feeding. Completing the information on the good-quality plants adapted to different environments will help to use and develop these valuable resources in a better way. In addition, it may be possible to improve rumen fermentation by aromatic pasture plants. Adiantum capillus-veneris (Adiantum) and Salvia officinalis L. (Salvia) are valuable genetic resources in pastures that are also used in livestock feeding. Due to the presence of plant secondary metabolites, they may improve rumen fermentation. However, there is little information on the nutritional value of Adiantum. Some information is available on the chemical composition of Salvia species (especially the leaves) and the effect of its essential oil on the rumen, but data on the use of the whole plant as forage are limited. Therefore, this study aimed to assess the nutritional value of Adiantum and Salvia compared to alfalfa, and the effect of including different levels of them in the diet on in vitro ruminal fermentation variables and digestibility.
The experimental pasture plants (Adiantum and Salvia) were obtained in July, after flowering, from the pasture of Safrin village located in the rural district of Rajaeedasht in western Alamut (Qazvin, Iran). In experiment I, the chemical composition of the fodders was determined by the standard methods, considering alfalfa as the control forage. In experiment II, the effect of different dietary levels of the fodders was assessed using in vitro gas production technique with five treatments including 1. A diet without the rangeland plants (control diet), 2. A diet containing 15% of Adiantum, 3. A diet containing 30% of Adiantum, 4. A diet containing 15% of Salvia, and 5. A diet containing 30% of Salvia (on a DM basis). The in vitro digestibility, fermentation variables, microbial biomass production (MBP), total antioxidant power (TAP), protozoa numbers, and methane production were determined. The gas test was performed in three replicates and two runs, and data were analyzed using the GLM procedure of SAS.
According to the results of experiment I, Adiantum and Salvia had higher ash compared to alfalfa (P<0.05). The crude protein and digestibility of Adiantum were lower than Salvia and alfalfa (P<0.05). The lower digestibility of Adiantum could be due to its higher lignin and ash and the lower crude protein concentration. Therefore, when consuming Adiantum in diets of high-productive ruminants, it is necessary to pay more attention to the use of energy supplements. Compared to alfalfa, the in vitro fermentation of Adiantum and Salvia resulted in higher in vitro ruminal MBP and TAP and lower ammonia-N and protozoa population (P<0.05), due to the presence of plant secondary metabolites such as phenolics, tannins, flavonoids, anthocyanins, and terpenes. The results of experiment II showed that the inclusion of Adiantum and Salvia in the diet had no significant (P>0.05) effect on in vitro gas production, organic matter digestibility, and metabolizable energy. Dietary use of Salvia, however, enhanced truly degraded substrate (P<0.05). Sometimes, high amounts of secondary metabolites in plants may have negative effects on the rumen but the amounts of metabolites in the pasture plants used in this study were not so high as to hurt rumen microbes and digestion. Dietary inclusion of Adiantum and Salvia improved in vitro TAP and decreased protozoa population, methane production, and acetate to propionate ratio (P<0.05). The lowest methane production was observed for the diets containing Salvia. The positive effect of the rangeland plants on in vitro TAP was because both plants contain significant amounts of various secondary metabolites (such as phenolic compounds, flavonoids, and terpenes) that are known to be favorable and high-capacity antioxidants. These plant metabolites can remove free radicals, bind transition metals (such as free iron), remove active oxygen from the environment, induce antioxidant enzymes, and reduce and moderate the conditions of oxidative stress and destruction. The reduction of methane release using Adiantum and Salvia in the diet was probably related to the fact that plant secondary metabolites destruct the protozoa or interfere with their metabolic pathways. In addition, they may inhibit methanogenic and hydrogen-consuming bacteria or hydrogen-producing Gram-positive bacteria. The dietary addition of Adiantum and Salvia improved in vitro ruminal MBP and decreased the ammonia-N concentration (P<0.05) compared to the control diet. The result could be due to the reduction of the protozoa population, causing a decrease in nitrogen recycling in the rumen and a decrease in bacteria predation. The formation of phenolic-protein complexes can also be another possible reason for reducing protein breakdown and ammonia concentration. Moreover, as rumen protozoa are reduced, the bacteria will have fewer natural predators and their population (reflected in the higher MBP) will increase, improving the degradation of feed ingredients. The inclusion of Adiantum and Salvia in the diet did not affect in vitro pH, total volatile fatty acids, and partitioning factor (P>0.05).
It is possible to include whole plants of Adiantum and Salvia in the diet, up to 30% DM, without adverse effects on digestibility. It also improves diet efficiency by increasing in vitro ruminal MBP and TAP and reducing methane and ammonia production.

In the animal husbandry industry, more than 70% of the production costs are related to nutrition. Among the nutrients consumed by livestock, protein is one of the most important and expensive nutrients. Due to Iran's limitations in the production of oilseeds and consequently the production of protein meals, providing the protein needs of livestock has been associated with many problems. The use of new and especially local protein sources in ruminant feeding is one of the main solutions to cover the lack of protein sources and reduce the import of these sources, and it also reduces production costs in the livestock and poultry industry. Camelina sativa medicinal-oil plant has attracted a lot of attention, especially in recent years, and its most important advantage is extreme resistance to drought and cold conditions. The presence of high amounts of crude protein (CP), energy, and essential amino acids in camelina meal makes it a useful and potential option for use in the livestock and poultry feed industry. It was shown that the CP content of camelina meal was 41.9% of dry matter. Also, camelina meal has higher CP content and similar rumen undegradable protein compared to canola meal. In terms of lysine and methionine amino acids, which are important in muscle growth, camelina meal is considered a rich source. Camelina is a plant with a short growth period of 85-100 days and recently in Iran at the beginning of the camelina development project, the DH1025 line was produced, which is cultivated under the name of Soheil variety on a wide scale. Various studies have been conducted on the use of camelina meal for different purposes in ruminant nutrition. This is while there is little information about the nutrition of camelina meal and especially Soheil variety in the nutrition of ruminants in Iran. Therefore, this research aimed to investigate the effects of different levels of camelina meal on growth performance, rumen fermentation parameters, blood metabolites, and nutritional behavior of Lori-Bakhtiari lambs.
Thirteen Lori-Bakhtiari male lambs of four to five months of age with a mean live weight of 34.5±5 kg were used for 70 days of the experimental fattening period. Lambs were assigned to three experimental treatments (10 lambs per treatment) in a completely randomized design. Three experimental diets contained camelina meal at levels of zero (control), five, and 10% of dry matter (DM). Experimental diets were formulated according to nutritional requirement tables for small ruminants and were similar in terms of energy and protein. Also, the ratio of forage to concentrate in the diets was considered to be 30 to 70. From the first day, the animals were kept and reared in individual stalls. Two weeks before the start of the experiment (adaptation period), the lambs were vaccinated against enterotoxemia and the amount of 20 mL of anti-parasitic syrup (5% Clozantel) per 10 kg of body weight and niclosamide anti-parasitic syrup (seven to 10 mL per lamb) was fed to the lambs. Camelina meal used in this project was a genetically modified and localized variety. Experimental rations were provided in a completely mixed form (TMR) to the lambs daily at 8:00 am and 4:00 pm.
Results showed that increasing the level of camelina meal in the diet increased linearly the concentration of ruminal ammonia, propionate, and blood urea nitrogen (P<0.05), while ruminal pH and other individual volatile fatty acids, and blood parameters were not affected by the experimental diets (P>0.05). The activity of carboxymethyl cellulase enzymes decreased linearly with increasing the level of camelina meal in the diet (P<0.05). However, the activity of other rumen microbial enzymes was not affected by the experimental diets (P>0.05). In terms of behavioral traits, diets had no effect on DM and NDF intake, and also final body weight and average daily gain (P>0.05). Except for the amount of rumination and the ratio of rumination to DM intake, which increased linearly with increasing the level of camelina meal in the diet (P<0.05), other nutritional behaviors were not affected by the experimental diets (P>0.05).
In general, the results of the present study showed that the use of camelina meal, as a new source of protein, instead of soybean meal up to 10% of dietary DM of fattening lambs is recommended.

Flax products (seed and meal) are one of the sources of energy and protein for ruminants. Although flaxseed is a very inexpensive and affordable source of omega-3s, more than 50% of its fatty acids are made from alpha-linolenic acid, but it cannot be used at high levels due to its anti-nutritional properties. Flaxseed processing improves nutrient consumption while reducing the negative effects of anti-nutritional substances such as lintine and making food more palatable. Various methods are used to process and improve the flaxseed digestion process, such as micronization and extrusion. The extrusion process is the process of processing high-temperature materials in a short time and is done by a combination of moisture, heat, mechanical energy, and pressure. Extrusion is also a technical function by which feed is processed, extruded, and cooked under a constant increase in pressure and then expanded due to a sudden pressure drop. Heat treatment applied during the extrusion process reduces the access of rumen bacteria to the fat in the diet by denaturing the protein matrix around fat droplets in oilseeds such as flaxseed and thus can reduce fatty acids. Microwave by microwave can be done after adding 25% moisture to the grains for three minutes in a device containing an infrared lamp. It was also found that micronization could be used to increase the degradable protein content of the rumen. This study was performed to evaluate the effect of flaxseed level and processing method on performance, skeletal growth indices, health, and ruminant behavior of suckling calves.
In this study, to investigate the effect of using different levels and methods of flaxseed processing on the performance of suckling calves, 35 newborn Holstein male calves with an initial weight of 41±4.5 kg were used. This experiment was performed in a completely randomized design with seven treatments and five replications. Treatments included: 1. Control, 2. The treatment contained 5% of raw flaxseed, 3. The treatment contained 10% of raw flaxseed, 4. The treatment contained 5% of micronized flaxseed, 5. The treatment contained 10% of micronized flaxseed, 6. The treatment contained 5% of extruded flaxseed, and 7. The treatment contained 10% of extruded flaxseed. The total trial period was 60 days, which included 14 days of adaptation. Stool consistency scoring was considered as a daily livestock health indicator for each calf. Measurement of skeletal growth rate was done by meter and caliper at the beginning and end of the period. To evaluate the effect of experimental treatments on calf performance, dry matter intake, daily weight gain, and feed conversion ratio were also measured.
Experimental treatments had no significant effect on daily feed intake, daily weight gain, and feed conversion ratio. Also, the growth of skeletal indices, fecal consistency, and rumination behavior was not affected by experimental treatments. The lack of effect on food intake probably indicates that the amount of linseed fatty acids used has a minimal mechanism of short-term regulation of feed intake. Oily seeds such as flaxseed contain eicosapentaenoic and docosahexaenoic fatty acids, both of which are active derivatives of linolenic acid. It is known that these oxygenated metabolites play an important role in the growth and development of infant animals, especially the development of their nervous system. However, eicosapentaenoic and docosahexaenoic fatty acids may have a lower effect on feed efficiency during this period of calves' life. In general, the duration of chewing is reduced by decreasing the size of particles and the content of insoluble fibers in neutral detergent. The lower content of insoluble fibers in the neutral detergent and its chemical and physical nature may have reduced rumination and chewing activity. Probably, the changes in the rumination time may be related to the difference in the dry matter consumed and the digestibility of the nutrients, and the rumination activity can also be considered a factor to diagnose rumen health due to the stimulation of saliva secretion. The duration of chewing activity (sum of eating and ruminating) can be a good measure of rumen health.
According to the results of this study, the use of processed flax did not hurt the performance, skeletal growth indices, and health of calves. Extruded and micronized flax can be used at the 10% level in the diet of suckling calves as a source of protein and energy.

Essential oils are volatile and concentrated liquids extracted from various parts of medicinal plants. In recent years, the use of essential oils in animal nutrition has gained interest as an alternative for antibiotic growth promoters. The main issue with using essential oils in poultry diets is the high volatility, which must be addressed by developing encapsulation techniques to preserve their efficacy. The purpose of the current experiment was to determine the effects of dietary supplementation of microencapsulated essential oil of Satureja khuzistanica on growth performance, oxidative stability of meat, and intestinal microflora of broilers.
A total of 320 1-d-old Ross 308 chicks were studied in a completely randomized design with a 2×4 factorial arrangement of treatments. The factors were two administration forms of essential oils (free and microencapsulated) and four levels of dietary supplementation (0, 50, 100, and 150 mg/kg). The experiment consisted of eight treatments, four replicates, and 10 broilers per replicate. The essential oil of Satureja khuzistanica was microencapsulated using a 2% sodium alginate solution, which was mixed and homogenized before being transferred into a funnel and dropped into a beaker containing a 5% calcium chloride solution using a needle from a syringe. The beads were gently stirred for an hour to solidify. After one hour, the beads were filtered through a sieve and washed with distilled water. The beads were thoroughly rinsed before being air dried at 23 °C for 12 hours and kept in airtight containers. Body weight and feed consumption were monitored in pens weekly. From these data, average daily gain (ADG), average daily feed intake (ADFI), and feed conversion ratio (FCR) were calculated weekly and throughout the entire rearing period. The European production efficiency factor (EEF) was also calculated for the whole rearing period. The minimum inhibitory concentration (MIC) of Satureja khuzistanica essential oil was determined by broth microdilution method for each of Escherichia coli, coliforms and lactobacillus bacteria. On day 42, two birds from each replicate were slaughtered and ileal samples were taken for microflora analysis. Total Escherichia coli, coliforms, and lactobacilli were enumerated in ileal digesta by the plate method using specific mediums. The thiobarbituric reactive substances (TBARS) assay was used to determine the oxidative lipid changes of the meat.
The in vitro results demonstrated that the MIC of savory essential oil against gram-negative Escherichia coli and coliforms was higher (0.276) than its MIC for gram-positive lactobacillus bacteria (0.069). Throughout the in vivo study, the ADFI of broilers fed the diet with 150 mg/kg of essential oil was lower than the control (103.3 vs. 108.8; P<0.05). The ADG of broilers fed 100 mg essential oil/kg of diet was more than those fed 150 mg/kg (60.1 vs. 54.2; P<0.05). Broilers fed microencapsulated essential oil in their diet had a higher (P<0.05) EEF than those fed free essential oil. The addition of savory essential oil at 100 and 150 mg/kg of diet reduced (P<0.05) the lipid peroxidation in broilers meat stored for 60 and 90 days compared to the control. Lipid peroxidation of meat was lower (P<0.05) in broilers fed microencapsulated essential oil in the diet than those fed free essential oils. The addition of savory essential oil at different levels of 50, 100, and 150 mg/kg diet reduced the count of coliforms in the ileum compared to the control (P<0.05). Moreover, the data indicated that the addition of the essential oil at 100 and 150 mg/kg diet reduced the number of Escherichia coli (P<0.05). The bacterial count of coliforms and E. coli was lower in broilers fed microencapsulated essential oil than those fed free essential oil.
The results of this study showed that supplementation of Satureja khuzistanica essential oil in the diet improved broilers' performance and intestinal microflora. Microencapsulation of savory essential oil with alginate improved broiler growth performance, EEF, and increased the antibacterial activity of the essential oil which resulted in a further decrease of pathogenic bacteria. According to the findings of this study, 100 mg of microencapsulated savory essential oil per kg of broilers’ diet can be recommended due to its beneficial effects on performance, oxidative stability of meat, and intestinal microflora.

Coccidiosis is a serious problem in the poultry industry, and medication is required continuously. There are several approaches to the control of coccidiosis. Several drugs have been used in the control of coccidiosis. The ionophore antibiotics such as lasalocid, maduramicin, monensin, narasin, and salinomycin are extensively used in poultry feed for the prevention or treatment of coccidiosis induced by Eimeria species. Unfortunately, the toxic effects of ionophores cause concern because of their narrow safety margin. Ionophores’ toxicity could be probably due to oxidative damage. Therefore, it can be prevented by the supplementation of antioxidants in the diet. It has been reported that 60 or 120 mg/kg of salinomycin caused some pathological changes in the liver, heart, kidney, and muscles, such as degeneration or necrosis of these tissues. However, administration of salinomycin with vitamin E or selenium showed that vitamin E decreases the pathological changes.  The present study aimed to investigate the effects of salinomycin administration in combination with some natural antioxidants on reducing salinomycin toxicity in laying chickens.
A total number of 400 day-old hy-line w36 chicks were used in a completely randomized design with five treatments and four replications for 35 days. Treatments were included: 1) control diet, 2) negative control diet containing 0.05% salinomycin sodium, 3) negative control + garlic powder (15 g/kg of diet), 4) negative control + selenium (450 mg/kg of diet) + vitamin E (2 g/kg of diet), and 5) negative control + zinc-methionine (160 mg/kg of diet). Body weight gain, feed intake, and body weight uniformity were measured weekly. Blood samples were taken to evaluate the levels of antioxidant enzymes, liver enzymes, electrolytes, and malondialdehyde levels at the end of the experimental period.
The results showed that the salinomycin diet (T2) decreased body weight and feed intake compared with the control diet in the total experimental period (P<0.05). But the addition of supplemental Zn-methionine to the diet (T5) led to improved body weight and feed intake (P<0.05). Significant differences were observed among various treatments for the relative weight of visceral organs (liver, heart, kidney, gizzard, proventriculus, intestine, and bursa of Fabricius), but there were no significant differences for spleen and lungs. Also, salinomycin increased the activity of liver enzymes including alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and serum malondialdehyde (MDA) in the negative control group and control group, and decreased the level of serum antioxidant enzymes compared to the control group (P<0.05), but the addition of vitamin E + selenium to the diet, eliminated the negative effects of salinomycin on these parameters (P<0.05). Vitamin E plays important roles in various biochemical and physiological processes, including antioxidation. The protective effect of vitamin E against the alterations induced by salinomycin on these estimated parameters in this study could be attributed to the role of vitamin E as a fat-soluble antioxidant, which protects the biological membranes from oxidative damage and decreases osmotic fragility of erythrocytes. Selenium also exerts its protective effect against oxidative damage by a decline in free radicals and increasing the synthesis of glutathione peroxidase, which catalyze the breakdown of toxic hydrogen peroxide and lipid hydroperoxides. Salinomycin decreased serum chlorine and increased serum potassium compared to the control group (P<0.05), and only the use of vitamin E + selenium adjusted these changes (P<0.05). The T2 group reduced the serum level of chlorine and increased the serum level of potassium (P<0.05). But there is no significant effect on the level of blood calcium. Although all treatments with antioxidants changed the levels of these electrolytes. The changes in electrolyte balance can result in metabolic alkalosis and acidosis. However, the T4 group only reduced the serum levels of potassium and calcium and increased the serum level of chlorine significantly, compared to the T2 group (P<0.05). However, there were no significant differences in the serum sodium and creatinine levels among various treatments.
Salinomycin administration in the diet of laying chicken induces undesirable effects on some estimated parameters probably due to oxidative damage. But, the supplementation of pullet diets with vitamin E and selenium can reduce the possible side effects of salinomycin.

Zebu cattle are highly adapted to tropical regions. However, females reach puberty after taurine heifers, which affects the economic efficiency of beef cattle breeding in tropical regions. A method to identify new loci and confirm existing quantitative trait loci (QTL) is through genome-wide association studies (GWAS). QTL-assisted selection and genomic regions affecting the production and reproduction traits have been considered to increase the efficiency of selection and improve production performance. The GWAS typically focuses on genetic markers with the strongest evidence of association. However, single markers often explain only a small component of the genetic variance and hence offer a limited understanding of the trait under study. A solution to tackle the aforementioned problems, and deepen the understanding of the genetic background of complex traits, is to move up the analysis from the single nucleotide polymorphism (SNP) to the gene and gene-set levels. In a gene-set analysis, a group of related genes that harbor significant SNP previously identified in GWAS is tested for over-representation in a specific pathway. The present study aimed to conduct a GWAS based on a gene-set enrichment analysis for identifying the loci associated with age at first calving trait using the high-density SNPs.

A total of 2273 Nelore cattle (995 males and 1278 females) genotyped using the Illumina BovineHD BeadChip were used in the current study. The association analysis included females with valid first calving records as well as open heifers. The association analyses were carried out by considering deregressed estimated breeding values (dEBV) for age at first calving as response variables. Before deregression, the estimated breeding values (EBV) were obtained for the dataset by considering both the calved and non-calved heifers. Variance components and EBV were obtained using the DMU software. In the analysis of AFC, a single-trait animal model was run. The gene-set analysis consists of three different steps: the assignment of SNPs to genes, the assignment of genes to functional categories, and finally the association analysis between each functional category and the phenotype of interest. The GWAS was evaluated using the GHap package in the R program. Using the biomaRt2 R package, the SNPs were assigned to genes if they were within the genomic sequence of the gene or within a flanking region of 15 kb up- and downstream of the gene. For the assignment of the genes to functional categories, the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway databases were used. The GO database designates biological descriptors to genes based on attributes of their encoded products and it is further partitioned into three components: biological process, molecular function, and cellular component. The KEGG pathway database contains metabolic and regulatory pathways, representing the actual knowledge of molecular interactions and reaction networks. Finally, a Fisher’s exact test was performed to test for overrepresentation of the significant genes for each gene-set.

The block sizes of five SNPs were chosen to perform association studies. Gene-set enrichment analysis has proven to be a great complement to GWAS. Among available gene-set databases, GO is probably the most popular, whereas KEGG is a relatively new tool that is gaining ground in livestock genomics. We hypothesized that the use of gene set information could improve prediction. However, neither of the gene set SNP classes outperformed the standard whole-genome approach. Gene-sets have been primarily developed using data from model organisms, such as mice and flies; therefore, some of the genes included in these terms may be irrelevant for reproduction. Gene-set enrichment analysis identified candidate genes related to estrogen metabolic process (HSD17B12), synapse organization (PPFIA2 and PPFIA2), sensory perception of mechanical stimulus (MYO3A and KCNMA1), protein tyrosine kinase activity (IGF1R), the cell-cell junction (FRMD4A), GnRH signaling pathway (ADCY5), and focal adhesion (PPP1R12A). Some of the genes which were found are consistent with some previous studies and are involved in biological pathways related to fertilization, age at first calving, estrogen biosynthesis, heifer conception rate, early development of the fetus, puberty, and glucose homeostasis in the ovary.  

This study supported previous results from GWAS of reproductive traits, and also revealed additional regions in the cattle genome associated with these economically important traits. These findings could potentially be useful for genetic selection in cows.

Generally, genetic markers, associated with metabolic pathways, might be used in marker-assisted selection to improve production and reproduction traits in farm animals. Especially, some traits with low heritabilities, such as reproduction and health traits could not be easily improved by classic selection strategies. However, the use of genetic markers and marker-assisted selection are considered powerful tools for the genetic improvement of low-heritable traits. Thus, detection of genetic markers associated with production and reproduction traits is an effective way to save endangered indigenous breeds, such as the Markhoz goat, a mohair-producing breed in Iran. The thyroid hormone-responsive (THRSP) gene is a candidate gene involved in thyroid hormone functions and the lipogenesis process. This gene is a protein-coding gene, with two exons, located on chromosome 29 in goats. There are some reports on the association of THRSP with production traits in farm animals. There are limited studies on metabolic pathways of THRSP and its associations with important economic traits in small ruminants and no study on the association of THRSP and reproduction traits was found in the literature. The aim of the present study was the investigation of the THRSP gene polymorphism and its association with body weight and litter size traits in Markhoz goats.

A total of 140 blood samples of Markhoz goats were randomly collected from the Research and Breeding Station in Kurdistan province in western Iran. Genomic DNA was extracted from whole blood samples. A pair of primers were designed using the Primer 3 online software to amplify a 486 bp fragment in THRSP gene exon 1. The designed primers were as follows:Forward: 5’-AGTCTGCGGGACTCCATATG-3’ Reverse: 5’-AAAATGGGACAGGCCATGT-3’ Polymorphism of the amplified fragment was investigated using the single-strand conformational polymorphism (SSCP) method and sequencing of three random samples for each SSCP pattern. The observed sequences were aligned to the GenBank reference sequence using the MegAlign module of DNAStar software and compared based on the Clustal W method. The sequences were translated by the Translate section of the ExPASy website (us.expasy.org/translatetool). Associations of body weight traits, including birth weight, three-month, six-month, nine-month, and 12-month body weights, with the observed genotypes were investigated using a general linear model, fitting genotype, birth year, birth type, and dam age as the fixed factors. The association of the observed genotypes with litter size was investigated using a two-way Chi-squared test. The SAS 9.4 program was employed for the association analyses.

In the studied samples, two different SSCP patterns and two single-nucleotide polymorphisms (SNPs) were detected in 148 and 173 bp locations of the studied fragment, as g.148G>A (resulting in Arginine to Glutamine amino acids exchange) and g.173A>G (a synonymous mutation), both as heterozygous loci. In the studied population, the frequency of the double-homozygous genotype, GG/AA (0.743), was noticeably higher than the double-heterozygous genotype, which is GA/AG (0.257). The alleles G and A had high frequencies, both equal to 0.871 in the 148 and 173 bp loci, respectively. Both loci had a significant deviation from Hardy-Weinburg equilibrium (P<0.0001). Polymorphism of the studied fragment did not have any significant effect on body weight traits. A significant association was observed between the detected genotypes and litter size. Whereby, litter size in double-heterozygous does (1.21) was significantly higher than the double-homozygous individuals (1.04), (P = 0.015). The present study is probably the first report on the association of the THRSP gene with litter size in goats. The THRSP is a protein which involves in thyroid hormone function and therefore might affect many metabolic pathways. However, a significant association of the observed genotypes with prolificacy is probably due to the role of THRSP in lipids metabolism and the association of lipids metabolism with reproduction performance.

The THRSP exon 1 is polymorphic in Markhoz goats. The studied fragment did not have any significant associations with body weight traits, but it had a significant effect on litter size. Based on the results of this study, the THRSP gene could be considered a candidate gene for litter size, and the detected SNPs at 148 and 173 bp of the studied fragment, could be used for marker-assisted selection in Markhoz goats. However, more studies on possible associations between THRSP polymorphism and production and reproduction traits are still needed in other goat breeds.

Beekeeping in Iran is one of the production activities that has unique characteristics. One of the characteristics of beekeeping is creating employment with the use of low capital. Therefore, beekeeping can be a good source of income for people with little capital. Although beekeeping is currently one of the low-income jobs, it is possible to increase the income of beekeepers by improving their technical efficiency. Efficiency is considered a very important factor in increasing the production and productivity of production resources, especially in the agricultural economy and rural development of developing countries. On the one hand, these countries face a lack of resources and limited opportunities, and on the other hand, they do not use the existing technologies efficiently; Therefore, studies related to the inefficiency in the production of livestock products and efforts to improve the efficiency and optimal use of resources in these countries will help to increase the productivity of production factors and increase the production of agricultural products. This study aimed to investigate the technological gap ratio (TGR) and factors affecting the technical efficiency of beekeeping in Rudsar Count in Guilan Province of Iran.

The required data were collected by completing questionnaires from 150 beekeepers in Rudsar County in 2020, which were determined using a random sampling method. In the present study, the data cloud method was used to identify the outliers in the data set. After deleting the outliers, the sample was divided into two homogeneous groups in terms of size using cluster analysis. The BCC model was used to estimate the technical efficiency relative to the group frontier and the metafrontier model was used to estimate the technical efficiency relative to the coverage frontier.

The results showed that the average TGR of the studied beekeepers is about 76%. This means that if all the studied beekeepers reach metafrontier technology, it is possible to increase production by 24%. Beekeepers that migrate have a higher technological gap ratio and the result of the Kolmogorov-Smirnov test showed that the difference in TGR is statistically significant. The results of multivariate regression of factors affecting technical efficiency showed that the variables of work experience, type of ownership, participation in training and extension classes, the main job of the beekeeper, number of beehives, and migration variable had a positive and significant effect on technical efficiency of beekeepers. Considering that there is a statistically significant difference between the TGR of beekeepers who migrate and do not migrate, so by solving the problems related to beekeeping migration, the level of beekeepers' production can be improved by using current resources. In the present study, the variable of the number of beehives and ownership had a positive and significant effect on the technical efficiency of beekeepers studied, so the technical efficiency of beekeepers can be increased by increasing the number of beehives and expanding private ownership.

By solving the problems related to the migration of beekeepers, it is possible to improve the production level of beekeepers by using current resources. In addition, by increasing the number of hives and developing private ownership, the technical efficiency of beekeepers can be increased. Considering that some farmers and gardeners do not allow beekeepers' hives to settle in their fields and gardens due to ignorance of the importance of bee pollination, it is necessary to promote cultural activities in this regard. Also, providing the necessary conditions for beekeepers to have easier and cheaper access to production inputs, such as giving low-interest loans, can increase the production of beekeepers and increase their income.