The incidence of obesity and its comorbidities, such as insulin resistance and type II diabetes, are increasing dramatically, perhaps caused by the change in the fatty acid composition of common human diets. Adipose tissue plays a role as the major energy reservoir in the body. An excess of adipose mass accumulation caused by chronic positive energy balance results in obesity. The n-3 polyunsaturated fatty acids (n-3 PUFA), DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) exert numerous beneficial effects to maintain physiological homeostasis. In the current review, the physiology of n-3 PUFA effects in the body is delineated from studies conducted in both human and animal experiments. Although mechanistic studies in human are limited, numerous studies conducted in animals and models in vitro provide potential molecular mechanisms of the effects of these fatty acids. Three aspects of n-3 PUFA in adipocyte regulation are discussed: (1) lipid metabolism, including adipocyte differentiation, lipolysis and lipogenesis; (2) energy expenditure, such as mitochondrial and peroxisomal fatty acid β-oxidation; and (3) inflammation, including adipokines and specialized pro-resolving lipid mediators. Additionally, the mechanisms by which n-3 PUFA regulate gene expression are highlighted. The beneficial effects of n-3 PUFA may help to reduce the incidence of obesity and its comorbidities.

The genetic markers associated with economic traits have been widely explored for animal breeding. Among these markers, single-nucleotide polymorphism (SNPs) are gradually becoming a prevalent and effective evaluation tool. Since SNPs only focus on the genetic sequences of interest, it thereby reduces the evaluation time and cost. Compared to traditional approaches, SNP genotyping techniques incorporate informative genetic background, improve the breeding prediction accuracy and acquiesce breeding quality on the farm. This article therefore reviews the typical procedures of animal breeding using SNPs and the current status of related techniques. The associated SNP information and genotyping techniques, including microarray and Lab-on-a-Chip based platforms, along with their potential are highlighted. Examples in pig and poultry with different SNP loci linked to high economic trait values are given. The recommendations for utilizing SNP genotyping in nimal breeding are summarized.

Changing dietary fatty acid composition in modern diet influences the prevalence of obesity. Increasing evidences suggest favorable effects of n-3 PUFA for protecting against obesity and the metabolic syndrome. However, the regulation of n-3 PUFA in adipose is still unclear. Thus, this study addressed metabolism of different dietary fats in the adipose tissue of porcine model. Eight-week-old cross-bred pigs were randomly assigned to three groups and fed a 2% fat diet for 30 days from either soybean oil (SBO), docosahexaenoic acid (DHA) or beef tallow. An in vitro experiment was conducted in which linoleic acid (LA), DHA or oleic acid (OA) were added to represent the major fatty acid in the SBO-, DHA- or BT- diets, respectively. Adipocytes size and lipid metabolism related genes were analyzed. Plasma triacylglycerol (TAG) was lower in DHA- than in BT-fed pigs, and the product of lipolysis, glycerol was highest in BT-fed pigs. In addition, expression of the lipolytic genes, adipose triglyceride lipase and hormone sensitive lipase was higher in BT-fed pigs and with OA treatment in vitro. DHA promoted protein kinase A activity in pigs without affecting lipolytic genes. Adipocyte cell sizes, TAG content and expression of lipogenic-related genes including, adipose differentiated related protein (ADRP) and diacylglycerol acyltransferase 1 (DGAT1) were elevated by DHA in vivo and in vitro, indicating DHA promoted adipogenesis to trap TAG in adipose tissue. Fatty acid β-oxidation genes were increased in the DHA-fed pigs. This effect was partly explained by the effect of DHA to promote adipogenesis to trap TAG in adipocytes and also increase expression of genes involved in adipocyte fatty acid oxidation. Therefore, our results suggest a direct effect of DHA on adipocyte metabolism, resulting in TAG turnover and fatty acid dissipation to facilitate plasma lipid uptake from the circulation.

The effects of different forms of multi-strain probiotics on weaning piglets are limitedly addressed. Thus, this study investigated the effects of live or inanimate multi-strain probiotics comprising Lactobacillus plantarum, Streptococcus thermophilus, and Bacillus subtilis on growth performance, intestinal morphology, fecal microbiota, short-chain fatty acids, and intestinal gene expression of weaning piglets. A total of 160 weaning piglets (4 weeks old) were randomly allocated into four treatments (CON: basal diet; AB: basal diet with 110 ppm and 66 ppm colistin in the weaning and nursery phases, respectively; LP: basal diet with 2.0 × 10⁹ CFU/kg live probiotics; and IP: basal diet with 2.0 × 10⁹ CFU/kg inanimate probiotics). Piglets fed with LP had significantly lower FCR compared to those of the CON and IP groups in week 4 to week 8 (p < 0.05). Moreover, the LP group had significantly higher villus height (VH) compared with AB at week 6, lower crypt depth (CD) compared with IP, and higher VH/CD ratio compared to other treatments at week 10 (p < 0.05), which indicate healthier intestinal morphology. Probiotic treatments (LP and IP) increased Bifidobacterium population compared to CON at week 6 and lowered Enterobacteriaceae at week 6 and week 10 (p < 0.05). Regarding gene expressions of intestinal integrity, LP showed significantly higher TFF3 expression compared with CON and AB at week 6 and compared with other treatments in jejunum at week 10 (p < 0.05). IP treatment had significantly higher MUC2 expression compared to other treatments at week 6 and week 10 (p < 0.05). Overall, live multi-strain probiotics improved growth efficiency by enhancing gut integrity and microbiome balance, making them a potential antibiotic alternative to ameliorate weaning stress and promote productive performance in weaning piglets.

Adult humans and mice possess significant classical brown adipose tissues (BAT) and, upon cold-induction, acquire brown-like adipocytes in certain depots of white adipose tissues (WAT), known as beige adipose tissues or WAT browning/beiging. Activating thermogenic classical BAT or WAT beiging to generate heat limits diet-induced obesity or type-2 diabetes in mice. Adiponectin is a beneficial adipokine resisting diabetes, and causing “healthy obese” by increasing WAT expansion to limit lipotoxicity in other metabolic tissues during high-fat feeding. However, the role of its receptors, especially adiponectin receptor 1 (AdipoR1), on cold-induced thermogenesis in vivo in BAT and in WAT beiging is still elusive. Here, we established a cold-induction procedure in transgenic mice over-expressing AdipoR1 and applied a live 3-D [¹⁸F] fluorodeoxyglucose-PET/CT (¹⁸F-FDG PET/CT) scanning to measure BAT activity by determining glucose uptake in cold-acclimated transgenic mice. Results showed that cold-acclimated mice over-expressing AdipoR1 had diminished cold-induced glucose uptake, enlarged adipocyte size in BAT and in browned WAT, and reduced surface BAT/body temperature in vivo. Furthermore, decreased gene expression, related to thermogenic Ucp1, BAT-specific markers, BAT-enriched mitochondrial markers, lipolysis and fatty acid oxidation, and increased expression of whitening genes in BAT or in browned subcutaneous inguinal WAT of AdipoR1 mice are congruent with results of PET/CT scanning and surface body temperature in vivo. Moreover, differentiated brown-like beige adipocytes isolated from pre-adipocytes in subcutaneous WAT of transgenic AdipoR1 mice also had similar effects of lowered expression of thermogenic Ucp1, BAT selective markers, and BAT mitochondrial markers. Therefore, this study combines in vitro and in vivo results with live 3-D scanning and reveals one of the many facets of the adiponectin receptors in regulating energy homeostasis, especially in the involvement of cold-induced thermogenesis.

Probiotics are widely used to improve intestinal health and production performance in the poultry industry. However, few studies have explored the effects of heat-killed probiotics. This study investigated the effects of a heat-killed probiotic mixture, comprising Bacillus subtilis (BS) and Lactobacillus plantarum 28 (LP28), on the growth performance, intestinal morphology, antioxidant capacity, and meat quality of broilers. A total of 300 Arbor Acres chicks were randomly assigned to four treatment groups (three replicates per group; 25 chicks per replicate): CON (basal diet), AB (basal diet + 10 ppm enramycin), LDP (basal diet + heat-killed LP28 and BS, 1.0 × 10⁸ cells/kg each), and HDP (basal diet + heat-killed LP28 and BS, 1.0 × 10⁹ cells/kg each). Feed intake was recorded daily, and body weight was recorded at the end of each growth phase. Twelve birds per treatment were used for intestinal morphology and antioxidant capacity analyses, and eight birds were used for meat quality analysis on day 35. One-way ANOVA followed by Tukey test was performed to perform statistical comparison among groups at p < 0.05. No significant intergroup difference was observed in growth performance. However, villus height and crypt depth were higher in the HDP group than in the CON and LDP groups (p < 0.05). The HDP group exhibited a stronger antioxidant capacity, higher hepatic glutathione peroxidase levels in the liver, and lower thiobarbituric acid reactive substance levels in breast meat than did the CON group (p < 0.05). The HDP group also exhibited better meat quality with lower shear force and higher gumminess and chewiness than did the CON group (p < 0.05). In summary, heat-killed probiotics may improve the intestinal morphology, antioxidant capacity, and meat quality of broilers and can be utilized in the poultry industry.