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ABSTRACT To demonstrate the role of gonadotropin-releasing hormone (GnRH) in yaks (Bos grunniens), we characterized the expression of gonadotropin-releasing hormone receptor (GnRHR) mRNA and protein. The level of GnRHR mRNA in the hypothalamus was higher than that in the pineal gland, pituitary gland, and ovary during estrus. Immunofluorescence analysis showed that GnRHR was expressed in the pinealocyte, synaptic ribbon, and synaptic spherules of the pineal gland and that melatonin interacts with GnRHR via nerve fibers. In the hypothalamus, GnRHR was expressed in the magnocellular neurons and parvocellular neurons. In the pituitary gland, GnRHR was expressed in acidophilic cells and basophilic cells. In the ovary, GnRHR was present in the ovarian follicle and Leydig cells. Gonadotropin-releasing hormone receptor is located in the pineal gland, hypothalamus, pituitary, and gonad during estrus of yaks and is mainly expressed in the hypothalamus and ovaries during the estrus period.

The high cost of feed ingredients, the use of non-renewable sources of phosphate and the dramatic increase in the environmental load resulting from the excessive land application of manure are major challenges for the livestock industry. Precision feeding is proposed as an essential approach to improve the utilization of dietary nitrogen, phosphorus and other nutrients and thus reduce feeding costs and nutrient excretion. Precision feeding requires accurate knowledge of the nutritional value of feedstuffs and animal nutrient requirements, the formulation of diets in accordance with environmental constraints, and the gradual adjustment of the dietary nutrient supply to match the requirements of the animals. After the nutritional potential of feed ingredients has been precisely determined and has been improved by the addition of enzymes (e.g. phytases) or feed treatments, the addition of environmental objectives to the traditional feed formulation algorithms can promote the sustainability of the swine industry by reducing nutrient excretion in swine operations with small increases in feeding costs. Increasing the number of feeding phases can also contribute to significant reductions in nutrient excretion and feeding costs. However, the use of precision feeding techniques in which pigs are fed individually with daily tailored diets can further improve the efficiency with which pigs utilize dietary nutrients. Precision feeding involves the use of feeding techniques that allow the provision of the right amount of feed with the right composition at the right time to each pig in the herd. Using this approach, it has been estimated that feeding costs can be reduced by more than 4.6%, and nitrogen and phosphorus excretion can both be reduced by more than 38%. Moreover, the integration of precision feeding techniques into large-group production systems can provide real-time off-farm monitoring of feed and animals for optimal slaughter and production strategies, thus improving the environmental sustainability of pork production, animal well-being and meat-product quality.O custo elevado das matérias-primas, o uso de recursos não renováveis de fosfatos e o aumento da poluição ambiental resultante do excesso de aplicação de dejetos no meio ambiente têm sido considerado um dos principais problemas na produção animal. A alimentação de precisão é proposta como uma abordagem essencial para melhorar a utilização do nitrogênio, fósforo e outros nutrientes oriundos da dieta e reduzir assim o custo da dieta e a excreção de nutrientes. A alimentação de precisão requer um conhecimento do valor nutricional dos ingredientes, exigência nutricional dos animais, formulação das dietas de acordo com as restrições ambientais e do adequado ajuste da oferta de nutrientes com a exigência dos animais. O conhecimento do potencial nutricional dos ingredientes de forma precisa e a melhora pela adição de enzimas (ex.: fitase) ou por tratamento (ex: térmico) associado ao uso de objetivos ambientais na formulação das dietas no método tradicional pode contribuir para o desenvolvimento de sistemas de produção de suínos sustentáveis devido reduzirem a excreção de nutrientes com pouco aumento no custo das dietas. O aumento do número de fases pode também contribuir na redução da excreção de nutrientes e custo das dietas. Entretanto, o uso de técnicas de precisão no qual os animais são alimentados de forma individualizada com dietas formuladas diariamente pode, além disso, melhorar a eficiência de utilização dos nutrientes das dietas pelos suínos. A alimentação de precisão compreende o uso de técnicas que permitem o fornecimento da quantidade e composição nutricional precisa do alimento diariamente e para cada suíno de uma população.Tem sido estimado que ao utilizar esse sistema pode resultar em uma redução de 4,6% no custo de alimentação e de aproximadamente 38% na excreção de nitrogênio e fósforo. Além disso, a integração de técnicas de alimentação precisa em sistemas de produção de grande porte permite o monitoramento em tempo real do alimento e do animal quando se trata de atingir ótimas condições de abate e estratégias de produção, melhorando assim a sustentabilidade da produção suína, bem estar animal e qualidade da carne.

ABSTRACT To explore the functions of Txnip and its mechanism in adipocyte differentiation, the preadipocytes were isolated from subcutaneous adipose tissue of three-day-old piglets and induced into adipogenic differentiation. The expression of Txnip and ChREBP was silenced, and the Txnip overexpression was achieved in the cells with transfection of the recombinant lentivirus strategies. Txnip silencing promoted the differentiation of porcine preadipocytes and PPARγ expression, and a PPARγ inhibitor reduced this facilitation. Instead, Txnip overexpression exerted a suppressive effect on the cell differentiation and PPARγ expression, and the PPARγ agonist offset this inhibition. High glucose stimulated the preadipocyte differentiation and expressions of ChREBP and Txnip. In contrast, Txnip expression was reduced by ChREBP silencing, suggesting glucose-regulated Txnip expression through the mediation of ChREBP. Moreover, the expressions of ChREBP and Glut4 induced by high glucose and glucose uptake of the cells were reduced by Txnip-overexpression, but increased by Txnip silencing, while these changes of Txnip did not alter their expressions under low glucose. Collectively, Txnip could be an inhibitor of porcine preadipocyte differentiation, which attenuated the adipogenesis through the negative feedback regulation on PPARγ. Txnip impaired the induction of glucose on the preadipocyte differentiation through decreasing Glut4 expression and glucose uptake and subsequent decrease of the expression and transcriptional activity of ChREBP.