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The present study evaluated the effects of dietary N-carbamylglutamate (NCG) on carcass traits, meat quality, and fatty acid profiles in the longissimus dorsi muscle and adipose tissues of Chinese Ningxiang pigs. A total of 36 castrated female pigs with a similar initial weight (43.21 ± 0.57 kg) were randomly assigned to two treatments (with six pens per treatment and three pigs per pen) and fed either a basal diet or a basal diet supplemented with 0.08% NCG for 56 days. Results showed that dietary NCG reduced shear force (p = 0.004) and increased drip loss (p = 0.044) in longissimus dorsi muscle of Ningxiang pigs. Moreover, increased levels of oleic acid (C18:1n9c) (p = 0.009), paullinic acid (C20:1) (p = 0.004), and α-linolenic acid (C18:3n3) (p < 0.001), while significant reduction in the proportions of arachidonic acid (C20:4n6) (p < 0.001) and polyunsaturated fatty acid (PUFA) (p = 0.017) were observed in the longissimus dorsi muscle of pigs fed NCG when compared with those fed the control diet. As for adipose tissues, the C20:1 (p = 0.045) proportion in dorsal subcutaneous adipose (DSA), as well as the stearic acid (C18:0) (p = 0.018) level in perirenal adipose (PA) were decreased when pigs were fed the NCG diet compared with those of the control diet. In contrast, the margaric acid (C17:0) (p = 0.043) proportion in PA were increased. Moreover, the NCG diet produced PA with a greater proportion of total PUFAs (p = 0.001) (particularly linoleic acid (C18:2n6c) (p = 0.001)) compared with those produced by the control diet. These findings suggest that dietary NCG has beneficial effects by decreasing the shear force and improving the healthfulness of fatty acid profiles, providing a novel strategy for enhancing meat quality of pigs.

As a main ingredient of milk, the nucleotides content is about 12−58 mg/g, which plays a critical role in maintaining cellular function and lipid metabolism. This study was conducted to evaluate the effects of short-term uridine monophosphate (UMP) and uridine (UR) administration on lipid metabolism in early-weaned piglets. Twenty-one weaned piglets (7 d of age; 3.32 ± 0.20 kg average body weight) were randomly assigned into three groups: The control (CON), UMP, and UR group, and oral administered UMP or UR for 10 days, respectively. The results showed that supplementation with UMP significantly increased (p < 0.05) serum low density lipoprotein (LDL) and tended to increase (p = 0.062) serum total cholesterol (TC) content of piglets when compared with the other two groups. Oral administration with UMP and UR significantly decreased (p < 0.05) the serum total bile acid (TBA) and plasma free fatty acids (FFA) of piglets, and significantly reduced the fatty acid content of C12:0 (p < 0.01) and C14:0 (p < 0.05) in liver. Experiments about key enzymes that are involved in de novo synthesis of fatty acid showed that the gene expression of liver X receptors (LXRα), sterol regulatory element-binding transcription factor 1 (SREBP1c), fatty acid desaturase 2 (FADS2), and fatty acid elongase 5 (ELOVL5) were remarkably down-regulated (p < 0.05) with UMP and UR treatment, and key factors of adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), and carnitine palmitoyl transferase 1 (CPT-1α) involved in fatty acid catabolism were also decreased (p < 0.05). Additionally, the protein expression of phosphorylated-mTOR was not affected while phosphorylation of AKT was repressed (p < 0.05). In conclusion, short-term oral UMP or UR administration could regulate fatty acid composition and lipid metabolism, thus providing energy for early-weaned piglets.

This study aims to investigate the effect of Calcium (Ca) feeding time on a sow’s productive performance and the profiles of serum mineral elements during late pregnancy and lactation. A total of 75 pregnant sows were assigned to three groups: The control (C), earlier-later (E-L), and later-earlier (L-E) groups. During late pregnancy, the C group was fed an extra 4.5 g Ca (in the form of CaCO3) at both 06:00 and 15:00, the E-L group was fed an extra 9 g Ca at 06:00, and the L-E group was fed an extra 9 g Ca at 15:00. Similar treatments with double the amount of Ca were applied during lactation. The results show that, compared with the C group, L-E feeding decreased the number of stillbirths and the duration of farrowing and placenta expulsion (FARPLA) and increased the average daily weight gain (ADG) of piglets. Similarly, E-L feeding increased the ADG of piglets (p < 0.05). Furthermore, both E-L and L-E feeding increased the Ca levels in sow serum and umbilical serum, and the Fe levels in umbilical serum, but decreased the Ca levels in the placenta and colostrum (p < 0.05). Experiments on the genes involved in mineral element transport showed that E-L feeding activated the mRNA expression of TRPV5, S100G, SLC30A7, SLC39A4, and Ferroportin1, while it inhibited the mRNA expression of ATP7A in the placenta (p < 0.05). Moreover, L-E feeding up-regulated the mRNA expression of ATP2B and IREB2, while it down-regulated the mRNA expression of ATP7B in the placenta (p < 0.05). In conclusion, the present study demonstrated that maternal Ca feeding at 15:00 h during late pregnancy and lactation decreased FARPLA and stillbirths and improved the growth performance of suckling piglets by altering the mineral element of the metabolism in the umbilical serum and milk, compared to conventional feeding regimes.