Cimin Long

Effects of the Sequence of Isocaloric Meals with Different Protein Contents on Plasma Biochemical Indexes in Pigs.

Nutrient composition and pattern of food intake may play a significant role in weight gain. The aim of this study was to document the effects of a daily 3-meal pattern with isocaloric diets containing different dietary protein contents on growth performance and different plasma biochemical indexes including amino acid plasma concentration in castrated male pigs. Then, 21 DLY (Duroc×Landrace×Yorkshire) pigs aged 60 days were assigned randomly into 3 groups: a control group (crude protein, CP 18.1%), a group receiving high then basal and then low CP meals (High-Low group) and a group receiving low then basal and then high CP meal (Low-High group) for 40 days with pigs being feed-restricted. On day 40, after 12 h fasting, blood samples were obtained for analysis. The results showed that the insulin/glucagon ratio was lower in the High-Low group (P<0.05) when compared with the control group. Compared with the control group, the average daily gain of pigs from the High-Low group increased by 14.10% (P = 0.046). Compared with the control group, serum gamma-glutamyl transferase (GGT) decreased significantly (P<0.05) in both the High-Low and Low-High groups. Plasma concentrations of branched-chain amino acids (BCAA: valine, isoleucine and leucine) increased in the Low-High group (P<0.05) when compared with the control group; and plasma methionine and serine decreased in both the two experimental groups (P<0.05). Compared with the High-Low group, all the BCAA increased significantly (P<0.05) in the Low-High group. These findings suggest that the sequence and quantity of alimentary protein intake affect the insulin/glucagon ratio, as well as amino acid concentrations including BCAA, methionine and serine. It is proposed that meal pattern with pigs receiving high then basal and then low CP meals daily may help to improve the weight gain of pigs.

Supplementation of the sow diet with chitosan oligosaccharide during late gestation and lactation affects hepatic gluconeogenesis of suckling piglets

Chitosan oligosaccharide (COS) has a blood glucose lowering effect in diabetic rats and is widely used as a dietary supplement. However, the effect of COS on the offspring of supplemented mothers is unknown. This experiment investigates the effect of supplementing sows during gestation and lactation on the levels of plasma glucose on suckling piglets. From day 85 of gestation to day 14 of lactation, 40 pregnant sows were divided into two treatment groups and fed either a control diet or a control diet containing 30mgCOS/kg. One 14 day old piglet per pen was selected to collect plasma and tissue (8pens/diet). Performance, hepatic gluconeogenesis genes and proteins expression, amino acids contents in sow milk, hepatic glycogen and free fatty acid were determined. Results showed that supplementation of the maternal diet with COS improved daily gain and weaning weight (P<0.05), and the concentration of amino acids in sow milk (P<0.05). Meanwhile, maternal supplementation with COS increased (P<0.05) mRNA expression levels and activities of PEPCK-C, PEPCK-M and G6Pase in the liver of piglets compared with piglets from control fed sows. Correspondingly, the level of plasma glucose was higher (P<0.001) and hepatic glycogen was lower (P<0.05) in piglets from COS fed sows when compared with that in the control group. In conclusion, dietary supplementation of the diet with COS during late gestation and lactation reduced piglet hypoglycemia by stimulating hepatic gluconeogenesis and improved the growth rate of suckling piglets.

Diurnal variations in polyunsaturated fatty acid contents and expression of genes involved in their de novo synthesis in pigs

The daily variations in circulating fatty acid (FA) contents and lipid metabolism have been well documented. However, whether long chain polyunsaturated FA (PUFA) contents and expression of genes involved in their de novo synthesis exhibit daily rhythms are yet unknown. We conducted the present study to investigate the daily variations in PUFA contents in plasma and liver of pigs. Moreover, diurnal expression of genes encode fatty acid desaturases and elongases, which are key enzymes catalyzed de novo synthesis of long chain PUFA, were also explored. The results showed that long chain PUFA contents in plasma and liver both exhibited diurnal rhythms. Diurnal variations were also observed in mRNA expression of FASD1 (Delta 5-desaturase), FASD2 (Delta 6-desaturase), ELOVL5 (fatty acid elongase 5) and ELOVL2 in liver, with an unexpectedly high level at night. Moreover, our results showed a similarity between the diurnal patterns of FASD1, FASD2, ELOVL2, ELOVL5 and Period 2. These results indicated a high activity of the desaturase-elongase pathway at night in pigs. These findings have important physiological and pathophysiological implications, since long chain PUFA are essential for cell function and closely involved in the development of metabolic syndrome.

Maternal chitosan oligosaccharide supplementation affecting expression of circadian clock genes, and possible association with hepatic cholesterol accumulation in suckling piglets

Chitosan oligosaccharide (COS) has been shown to reduce lipid accumulation in liver in mice and rats. The purpose of this study was to investigate whether maternal COS feeding affects hepatic lipid metabolism via influencing the expression of circadian clock genes in piglets. From day (d) 85 of gestation to d 14 of lactation, sixteen pregnant sows were divided into a control group (basal diet without COS supplementation) and a COS group (30 mg COS/kg basal diet). After farrowing, one piglet per litter in each group was selected for the collection of plasma and liver samples on d 0 and d 14 of age, respectively. Interestingly and significantly, we found that maternal COS supplementation promoted plasma and hepatic cholesterol accumulation and up-regulated the mRNA level of negative-regulated element period 1 (Per1), and reduced the abundance of the positive elements, circadian locomotor output cycles kaput (CLOCK), and brain muscle Arnt-like 1 (BMAL1) in the suckling piglets on d 14. These alterations may promote the hepatic cholesterol accumulation, which, in turn, activates hepatic bile acid metabolism and attenuates the relative expression levels of lipid metabolism-associated genes in the liver. However, the expression of CLOCK and BMAL1 and the lipid profile in the plasma and liver were not affected by COS supplementation on d 0. Collectively, our results indicate that maternal supplementation with COS postpartum up-regulates cholesterol accumulation in suckling piglets at age d 14, in part, by the regulation of circadian clock genes.

Effects of a daily three‐meal pattern with different dietary protein contents on pig growth performance, carcass and muscle quality traits

BACKGROUND Recent research related to phase-feeding programmes for pig nutrition do not always account for the variation among individuals, and feeds are usually formulated to optimise the performance of the whole pig population. This study aimed at measuring the effects of a daily three-meal pattern with different dietary protein contents on pig growth performance, carcass and muscle quality traits. RESULTS The results showed that compared with the 3C treatment, average daily gain (ADG) of pigs in the HCL treatment increased by 14.75% (P < 0.05) during period 1. The carcass weight (P = 0.006) and slaughter weight (P = 0.021) in the HCL group increased when compared with those in the 3C and LCH treatments. Moreover, the LCH feeding sequences contributed to reduce the drip loss in longissimus dorsi (LD) muscle (P < 0.05) when compared with the 3C treatment. The HCL or LCH feeding sequence contributed to increase the meat quality when compared with those receiving the 3C treatment. CONCLUSION Collectively, our results indicate that feeding high protein meal in the morning and a gradual reduction of the protein content in meals over the day may improve muscle quality characteristics, maximise performance, and reduce the pig feed cost.

Effects of iron status on expression of circadian clock genes and serum lipid metabolism in sucking piglets

ABSTRACT The aim of the study is to determine the effects of iron on circadian clock gene expression and serum lipid metabolism in sucking piglets. Twenty-four neonatal piglets were selected and randomly assigned into three groups (A, B, and C) with eight replicates. Group A were received 1 mL physiological saline by intramuscular administration at d 3 and d 10; group B were received 1 mL iron dextran (100 mg) by intramuscular administration at d 3 and 1 mL physiological saline at d 10, respectively; group C were received 1 mL of iron dextran (100 mg) by intramuscular administration at both d 3 and d 10. Our results reveal that the relative expressions of Cry1, Cry2, Per1, Per2, and Bmal in liver were significantly different in the three groups (p < 0.05). Meanwhile, the content of triglyceride (TG) and high-density lipoprotein (HDL) in serum were also affected by the iron supplementation (p < 0.05). These results indicated that iron affected hepatic circadian clock genes significantly, meanwhile, it may possible association with lipid metabolism.

A Maternal Two-meal Feeding Sequence with Varying Crude Protein Affects Milk Lipid Profile in A Sow-Piglet Model

The effects of a two-meal feeding sequence on production performance and milk lipid profile were investigated. Sixty pregnant sows (d 85 of gestation) were assigned to 3 groups: 2 C group (fed a control crude protein [CP] diet at 0600 and 1500 daily), LH group (fed a low CP diet and a high CP diet at 0600 and 1500), or HL group (fed a high CP diet and a low CP diet at 0600 and 1500). Reproductive performance of sows, and lipid profiles of plasma and milk were measured. Results showed that the HL feeding sequence dramatically increased average piglet weight/litter, average daily gain of piglet/litter, and milk production of sows. LH feeding sequence increased milk fat proportion, and HL feeding sequence significantly increased the proportion of milk MUFA on d 14 and 21 of lactation. Interestingly, the HL feeding sequence also reduced the ratio of C18:1cis/C18:1trans in milk, which may account for the greater milk production of sows and growth performance of piglets during lactation. These findings indicated that both the maternal two-meal feeding sequences with varying crude protein improved milk production and milk lipid profiles of sows, which might contribute to improving growth performance of piglets.

Dietary supplementation of Lonicera macranthoides leaf powder improves amino acid profiles in serum and longissimus thoracis muscle of growing-finishing pigs

A 60-days feeding trial was conducted to determine the effect of dietary supplementation of Lonicera macranthoides leaf (LML) on growth performance, meat quality, and free amino acid profiles in growing-finishing pigs. L. macranthoides leaves were harvested, air-dried and milled to powder. A total of 288 crossbred barrows (Large White × Landrace) with an average initial BW of 54.0 ± 3.4 kg were randomly allocated to 3 treatment groups and fed either a basal diet or a diet supplemented with 0.5% or 1.0% LML powder. Results showed that diet supplemented with LML powder did not affect average daily feed intake (ADFI) and feed: gain ratio (P > 0.05) in growing-finishing pigs. Moreover, diet supplemented with LML powder showed no significant effects on carcass traits (P > 0.05) including dressing percentage, backfat thickness and loin muscle area, and meat quality traits (P > 0.05) including meat color, intramuscular fat and cooking loss. However, diet supplemented with LML powder significantly improved free amino acid profiles in serum and longissimus thoracis muscle in growing-finishing pigs. Most importantly, dietary LML powder increased total free amino acids content (P < 0.001) and essential free amino acid content (P < 0.001) in longissimus thoracis muscle. These results indicate that LML has the potential to improve the nutritional value of meat through improving free amino acid profiles.

Diurnal variations in methionine content and expression of certain genes involved in DNA methylation reaction in pigs

Abstract Whether methionine content and its metabolites in liver and skeletal muscle show diurnal rhythmicity remains unknown. In the present study, we investigated the diurnal rhythms in methionine and S-adenosylmethionine (SAM) in plasma, liver, and longissimus thoracis muscle, as well as in enzymes involved in methionine-related transmethylation reaction using pigs maintained in a 12-h photoperiod. The results showed that concentration of methionine and SAM, as well as mRNA expression of methionine adenosyltransferase (MAT1A), DNA methyltranferase (DNMT3A and DNMT3B) in liver showed diurnal rhythmicity. Comparison with typical circadian clock genes revealed a similarity between the diurnal patterns of MAT1A and cryptochrome circadian clock 1 (CRY1) expression, whereas the daily patterns of MAT2A, DNMT3A, and DNMT3B expression were reversely related to the expression patterns of Timeless. These results imply that much attention should be paid to rhythms of methionine metabolism and methylation activity in the pathogenesis of diseases, such as cancer and metabolic syndrome.