Knockdown of CPT1A Induce Chicken Adipocyte Differentiation to Form Lipid Droplets

Lipid metabolism dysfunction is closely related to obesity, inflammation, diabetes, lipodystrophy, cardiovascular disease. Along with having a positive effect on energy homeostasis during fasting or prolonged exercise through mitochondrial fatty acid oxidation (FAO), more than two dozen enzymes and transport proteins are involved in the activation and transport of fatty acids into the mitochondrial, providing insights into their critical roles in metabolism. CPT1A has been reported to be expressed ubiquitously in the body and associated with dire consequences affecting fat deposition as the key rate-limiting enzyme of FAO. However, there is a dearth of data on the specific role of CPT1A on adipogenic differentiation and adipocyte lipolysis on chicken. This study assessed CPT1A's function in adipocyte differentiation andadipocyte lipolysis, and the mechanisms were investigated. We found that CPT1A knockdown (KD) promotes the differentiation of chicken preadipocytes into mature adipocytes. CPT1A KD increased PPARγ protein expression level. Expression levels of lipid synthesis-related genes were increased, and lipolysis genes were reduced. Also, CPT1A KD can encourage the formation of lipid droplets. So our results confirmed that knockdown of CPT1A induced the lipid differentiation and inhibited the ß-oxidation process to promote the formation of lipid droplets. These findings may deepen our understanding on CPT1A function, especially its regulatory role in adipocyte biology.(AU)

Identification and characterization of SREBF2 expression and its association with chicken carcass traits.

The sterol regulatory element-binding transcription factor 2 gene (SREBF2) plays an important role in regulating lipid homeostasis. To reveal the genetic factors that underlie carcass fat deposition in chickens, we cloned the coding DNA sequence of chicken SREBF2, investigated SREBF2 mRNA expression levels in various tissues, detected single nucleotide polymorphisms (SNPs) in the exon regions of the gene, and conducted association analyses between single markers/haplotypes and carcass traits. The entire 2859-bp cDNA sequence of chicken SREBF2 that encoded 952 amino acids was obtained and characterized. SREBF2 mRNA was highly expressed in the uropygial gland, followed by the liver, breast muscle, and leg muscle. Ten SNPs were detected, and four (g.49363077T>A, g.49357503C>T, g.49355533G>A, and g.49354641G>A) were novel. When analyzing the associations between the single mutations and carcass traits, significant differences were found in three SNPs and g.49357915G>A was highly significantly associated with most carcass traits, except for abdominal fat weight and sebum thickness. In addition, haplotype combinations that were constructed using the SREBF2 SNPs were associated with breast muscle weight. Chickens with the combined genotype H21H21 had the highest live weight, carcass weight, eviscerated weight, and semi-eviscerated weight values. To the best of our knowledge, this is the first study conducted on chicken SREBF2 polymorphisms, which are predictive of the genetics that underlie the economic performance of chickens.

Expression patterns of melatonin receptors in chicken ovarian follicles affected by monochromatic light.

Artificial illumination is an important exogenous factor in the control of many physiological and behavioral processes as well as an important environmental factor in the management of laying hens. Melatonin receptors are members of the G protein-coupled receptor family. The hormone melatonin is secreted primarily by the pineal gland, with highest levels occurring during the dark period of a circadian cycle. The aim of this study was to examine the effect of monochromatic light on chicken egg reproduction and expression of melatonin receptors in chicken ovarian follicles. A total of 552 19-week-old hens were randomly divided into 4 groups with 138 birds in each group. Each group was randomly divided into 3 replicates with 46 birds in each replicate. Feed and water were provided for ad libitum. Light treatments were: control cool white (400-760 nm), blue (480 nm), green (560 nm), and red (660 nm). The short wavelength (blue light) group produced a greater total number of eggs at 300 days of age than did the long wavelength (red light) group, and the red light group showed higher melatonin receptor type 1A and melatonin receptor type 1C mRNA and protein expression. These results suggest that the wavelength of light is closely related to chicken egg number at 300 days of age; there is no effect of monochromatic light on melatonin receptor type 1B.

Effects of sex and age on chicken TBC1D1 gene mRNA expression.

The objective of this study was to investigate the effects of sex and slaughter age of chickens on fatty acid composition and TBC1D1 gene expression in 4 different tissues: breast muscle, thigh muscle, abdominal fat, and subcutaneous fat. Sixty Erlang mountainous chickens (hybrid SD02 x SD03) were raised under the same conditions and slaughtered at 8, 10, and 13 weeks of age. The results showed that the sex of the animal significantly affected the content of arachidic acid (C20:0), sinapic (C22:1), linoleic (C18:2n-6), eicosapentaenoic (C20:5n-3), and docosahexaenoic acids (C22:6n-3), whereas other fatty acid contents were not affected. Age had a significant effect on most monounsaturated fatty acids, except for octadecenoic acid (C18:1). TBC1D1 mRNA was abundant in all tissues at all 3 ages of slaughter. Cocks exhibited higher TBC1D1 mRNA levels than hens in the thigh muscle and abdominal fat at 10 and 13 weeks, respectively.