RBST Progress in Livestock Conservation Science

Polygenic hereditary traits of young pigs and their association with the melanocortin receptor gene–4 (MC4R)


Khalak, V.I. and Gutyj, B.V., 2020. Polygenic hereditary traits of young pigs and their association with the melanocortin receptor gene–4 (MC4R). Scientific Messenger of LNU of Veterinary Medicine and Biotechnologies. Series: Agricultural sciences, 22(93), pp.84-89.

The article presents the results of studies of fattening and meat qualities of young pigs of different genealogical lines of large white breed and genotypes by the gene of melanocortin receptor – 4 (MC4R). The research was conducted in “Druzhba-Kaznacheyivka” LLC, the genetics laboratory of the Institute of Pig Breeding and APV NAAS and the animal husbandry laboratory of the State Institution Institute of Grain Crops NAAS. The work was performed according to the research program of NAAS №30 “Innovative technologies of breeding, industrial and organic production of pig products” (“Pig Breeding”). DNA-typing of the melanocortin-4 receptor gene (MC4R) was performed by Kim K., Larsen N., Short T. et al. (2000). Evaluation of young pigs for fattening and meat qualities was carried out taking into account the following quantitative characteristics: the average daily increase in live weight during the period of control fattening, g; age of live weight 100 kg, days; fat thickness at the level of 6–7 thoracic vertebrae, mm; the length of the cooled carcass cm; the length of the bacon half of the cooled half-carcass, cm. The length of the cooled carcass was measured with a measuring tape from the edge of the fusion of the pubic bones to the anterior surface of the first cervical vertebra; the length of the bacon half of the cooled half-carcass - from the anterior edge of the pubic bone to the middle of the anterior edge of the first rib (Berezovsky, Khatko, 2005). Conditions for feeding and keeping young pigs of the experimental groups were identical and complied with zootechnical standards. Economic efficiency of use of animals of various genotypes (МС4RАА, МС4RАG) and biometric processing of the received data (Lakin, 1990). calculated according to generally accepted methods. It is established that young pigs of large white breed of controlled population at the age of reaching live weight of 100 kg exceed the minimum requirements of the elite class by 6.73, fat thickness at the level of 6–7 thoracic vertebrae – 30.84, length of chilled carcass – 3.52 %. Significant difference between animals of different genotypes by melanocortin 4 receptor gene (МС4RАА, МС4RАG) was established by the average daily gain of live weight during the control period of fattening, the age of reaching live weight of 100 kg, fat thickness at the level of 6–7 thoracic vertebrae, length half of the cooled half-carcass and a complex index of fattening and meat qualities (B. Tyler's index). Young pigs of large white breed line Kotilo UA 8819347 outperformed peers line Azuro UA 8800557 on average daily live weight gain during the control period of fattening by 5.29%, the age of 100 kg live weight – 3.29 %, fat thickness at the level of 6–7 breasts vertebrae – 7.14 %. The longer length of chilled carcass (by 1.13 %) and the length of bacon half of chilled half carcass (by 2.68 %) were characterized by animals of Azuro UA 8800557. The correlation coefficient between fattening and meat qualities in young pigs of large white breed of the controlled herd varies ranging from –0.865 (tr = 22.26, P < 0.001) to +0.913 (tr = 35.43, P < 0.001). The maximum increase in additional products was obtained from young pigs of the МС4RАG genotype (+2.57 %) and the genealogical line Kotilo UA 8819347 (+4.86 %), and its cost is +694.26 – 1312.88 UAH/head. in accordance.


PROSPECTS OF APPLICATION OF ARTIFICIAL FERTILIZATION FOR OBTAINING PIG EMBRYOS IN VITRO


Shcherbak, O.V. and Lyzohub, O.Y., 2020. PROSPECTS OF APPLICATION OF ARTIFICIAL FERTILIZATION FOR OBTAINING PIG EMBRYOS IN VITRO. Animal Breeding and Genetics, 60, pp.116-124.

Literary data about the method using artificial insemination for receiving pigs’ embryos in vitro (intracytoplasmic injection spermatozoon in oocyte (ICSI – Intracytoplasmic sperm injection)) for application of such approach to preserve and improve the gene pool of domestic pig breeds were presented. In pig breeding there is a threat of extinction of breeds due to periodic outbreaks of infectious diseases. Scientists are constantly paying attention to the preservation of the gene pool of this species, but approaches to cryopreservation of gametes and embryos still do not provide stable and high results. Some biotechnological manipulations were only informative, although practical approaches to gene pool conservation are essential. The ICSI method is an artificial insemination of oocytes in vitro during which one spermatozoon is injected into a mature oocyte at the stage of metaphase II meiosis. It is currently well established on female oocytes, but for oocytes of other mammalian species remains insufficiently optimized to achieve the same percentage of fertilization and embryo formation. In our country there is very little data on the use of ICSI method for artificial insemination of animals, including pigs, although this method will increase the efficiency of fertilization and the formation of full-fledged pig embryos in vitro. It was shown that the level of blastocyst formation in pigs that were cleaved from thawed immature oocytes fertilized by ICSI was 5.2%. It has been proven that the efficiency of fertilization by a modified ICSI method increases when using hyaluronic acid for sperm selection called PICSI. Because only mature sperm have a receptor for hyaluronic acid, which is contained on the zona pellucida of the oocyte, so only mature spermatozoa are selected for fertilization. It has long been thought that damage to the head of the sperm leads to damage to the genetic material, which in turn leads to lack of fertilization or the formation of abnormal embryos. Therefore, among the requirements for ICSI the main was the damage of the tail and avoidance of the sperm head and neck injury. Disulfide bridges of the sperm head, which are formed through the passage through the epididymis, have been shown to make the sperm nucleus resistant to chemical and physical ruptures. Chinese scientists published in 2020 the results of studies on the treatment of oocytes during the ICSI procedure with urhodeoxycholic acid and showed that this approach increases the percentage of zygotes obtained. This phenomenon is explained by the ability of this substance to reduce oxidative stress caused during this procedure in the endoplasmic reticulum and prevent apoptosis. Thus, the ICSI method provides effective fertilization with the involvement of a minimum number of sperm, which is extremely convenient in working with extinct species and species that are on the verge of extinction. Our data on the application of the ICSI method with various modifications indicate the prospects for the application of the ICSI method for its implementation in practice.

Whole genome variants across 57 pig breeds enable comprehensive identification of genetic signatures that underlie breed features Xu, J., Fu, Y., Hu, Y., Yin, L., Tang, Z., Yin, D., Zhu, M., Yu, M., Li, X., Zhou, Y. and Zhao, S., 2020. Whole genome variants across 57 pig breeds enable comprehensive identification of genetic signatures that underlie breed features. Journal of Animal Science and Biotechnology, 11(1), pp.1-16. A large number of pig breeds are distributed around the world, their features and characteristics vary among breeds, and they are valuable resources. Understanding the underlying genetic mechanisms that explain across-breed variation can help breeders develop improved pig breeds. In this study, we performed GWAS using a standard mixed linear model with three types of genome variants (SNP, InDel, and CNV) that were identified from public, whole-genome, sequencing data sets. We used 469 pigs of 57 breeds, and we identified and analyzed approximately 19 million SNPs, 1.8 million InDels, and 18,016 CNVs. We defined six biological phenotypes by the characteristics of breed features to identify the associated genome variants and candidate genes, which included coat color, ear shape, gradient zone, body weight, body length, and body height. A total of 37 candidate genes was identified, which included 27 that were reported previously (e.g., PLAG1 for body weight), but the other 10 were newly detected candidate genes (e.g., ADAMTS9 for coat color). Our study indicated that using GWAS across a modest number of breeds with high density genome variants provided efficient mapping of complex traits. Effect of migration, distribution and spacing of pig embryos on pregnancy and fetal survival Dziuk, P., 1985. Effect of migration, distribution and spacing of pig embryos on pregnancy and fetal survival. Journal of reproduction and fertility. Supplement, 33, pp.57-63. Pig embryos enter the uterus from the oviduct about 48 h after ovulation at about the 4-cell stage. They remain near the tip of the uterine horn until about Day 6 when they migrate towards the body of the uterus. By Day 9 some embryos have entered the horn opposite the one of origin and continue migrating until Day 12. At Day 12 embryos can no longer successfully move to a different site. The critical signal for recognition of pregnancy occurs at Day 12 at the same time that embryos are elongating at a rapid rate. The distribution of embryos throughout the length of the horns has occurred by this time and spacing accompanied by uterine growth takes place. The speed of migration is not influenced by the number of embryos but may be affected by secretions from the embryos acting on the uterus. A significant section of unoccupied uterus at Day 12 will prevent continuance of pregnancy regardless of the number of embryos present in the occupied section. When the number of embryos is so few as to not occupy the uterus fully, pregnancy will not continue. Removal of embryos from a significant section of the uterus after Day 14 does not stop an existing pregnancy. Embryos are spaced nearly equidistant from each other with the absolute space between fetuses dependent on the total uterine space available. The position of the fetus in the uterus affects the spacing between fetuses; fetuses at the tip of the horn before Day 25 have the greatest space with the space decreasing from the tip to the body.

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