Comparison of long term lipogenic effects of two different medium-chain triglycerides (tri C8: O and tri C12 : O) in the growing rat

Docosahexaenoate-enriched fish oil and medium chain triglycerides shape the feline plasma lipidome and synergistically decrease circulating gut microbiome-derived putrefactive postbiotics

The purpose of this study was to examine the influence of medium-chain fatty acid-containing triglycerides (MCT), long-chain polyunsaturated fatty acid-containing triglycerides, and their combination on the plasma metabolome of cats (Felis catus), including circulating microbiome-derived postbiotics. After a 14-day lead-in on the control food, cats were randomized to one of four foods (control, with 6.9% MCT, with fish oil [FO; 0.14% eicosapentaenoate, 1.0% docosahexaenoate], or with FO+MCT; n = 16 per group) for 28 days. Analysis of plasma metabolites showed that the addition of FO and MCT led to synergistic effects not seen with either alone across a number of lipid classes, including fatty acids, acylcarnitines, and acylated amines including endocannabinoids. Notably, the FO+MCT group had an increase in ketone body production relative to baseline and beyond that seen with MCT alone. N-acyl taurines, the accumulation of which has been implicated in the onset of type 2 diabetes, were significantly decreased in the FO+MCT group. Significant decreases in the gut microbiome-derived postbiotic classes of indoles/indolic sulfates and phenols/phenolic sulfates were observed only the FO+MCT group. Overall, the combination of MCT and FO led to number of changes in plasma metabolites that were not observed with either oil alone, particularly in postbiotics.

Effects of dietary coconut oil on fatty acid oxidation capacity of the liver, the heart and skeletal muscles in the preruminant calf

The oxidative capacity of the liver, the heart and skeletal muscles for fatty acids were investigated in preruminant calves fed for 19 d on a milk-replacer containing either coconut oil (CO, rich in 12:0) or tallow (rich in 16:0 and 18:1). Weights of the total body and tissues did not differ significantly between the two groups of animals but plasma glucose and insulin concentrations were lower in the CO group. Feeding on the CO diet induced an 18-fold increase in the hepatic concentration of triacylglycerols. Rates of total and peroxisomal oxidation of [1-14C]laurate, [1-14C]palmitate and [1-14C]oleate were measured in fresh tissue homogenates. Higher rates of total oxidation in liver homogenate and of peroxisomal oxidation in liver, heart and rectus abdominis muscle homogenates were observed with laurate used as substrate. Furthermore, the relative contribution of peroxisomes to total oxidation was 1·9-fold higher in the liver and in the heart with laurate than with oleate or palmitate. Finally, the peroxisomal oxidation rate of oleate was 1·5-fold higher in the hearts of calves fed on the CO diet. Whatever the tissue, citrate synthase (CS, EC 4.1.3.7) and cytochrome c oxidase (COX, EC 1.9.3.1) activities were similar between the two groups of calves but the COX : CS activity ratio was lower in the liver of the CO group. In conclusion, laurate is better catabolized by peroxisomes than long-chain fatty acids, especially in the liver. Elongation of lauric acid after partial oxidation might explain the hepatic triacylglycerol accumulation in calves fed on the CO diet.

The metabolic fate of the amido-N group of glutamine in the tissues of the gastrointestinal tract in 24 h-fasted sheep

Whole-body and gastrointestinal tract (GIT) metabolism of [5-15N]glutamine were monitored in lambs (33 kg live weight) fasted for 24 h. Animals were previously prepared with vascular catheters across the mesenteric-(MDV) and portal-drained viscera (PDV) to permit quantification of mass and isotopic transfers of metabolites by arterio-venous difference. Continuous infusions of [5-15N]glutamine into the jugular vein were conducted for 10 h and integrated blood samples withdrawn over 75 min intervals for the last 5 h of infusion. The lambs were then killed and portions from various tissues of the digestive tract and other body organs removed for determination of15N enrichment in RNA, DNA and protein (the latter obtained by difference using total acid-precipitable N). Whole-body glutamine flux was 108 μmol/min of which 23 and 47 % could be attributed to MDV and PDV metabolism (P< 0·001) respectively. There was a small net production of glutamine across the MDV. GIT blood-flows and NH3production were partitioned 3:2 between MDV and non-MDV components. Less than 5 % of the NH3produced was derived from the amido-N of glutamine, while across the small intestine (MDV) 26 % of the glutamine flux was converted to NH3, compared with 18 % for non-MDV transfers. The15N enrichments in protein were of the order jejunum > duodenum > ileum with mucosal cells more labelled than serosal (P< 0·001). Lesser enrichments were observed for other GIT tissues (abomasum > caecum > rumen) while liver and lymph were comparable with the abomasum; kidney, spleen and muscle were lower still (P< 0·05). Enrichments of RNA were similar to that of protein and followed the same pattern, except for higher relative values for liver, spleen and lymphoid tissue. The lowest enrichments were observed for DNA, but again the pattern order was similar except for increased label in lymph, caecum and the spleen. For the MDV there was reasonable agreement between15N-disappearance as glutamine and appearance in NH3(24 %), protein (81 %), RNA (3·6 %) and DNA (2·1 %). For the total PDV there was a shortfall (−12 %), however, which may be due to losses in lumen components. These results show the importance of the GIT as a contributor to total glutamine plasma flux, but indicate a lesser reliance on glutamine metabolism by the digestive tract of the ruminant compared with observations from non-ruminants.

Effects of substitution of tricaproin for tallow and of protein concentration in milk substitutes on nitrogen and energy balance in the preruminant lamb

1. Results of 138 nitrogen balance studies from experiments with forty male Limousin and nineteen male Ile de France preruminant lambs were used to estimate total N requirements and to assess the effects of dietary tricaproin inclusion, protein concentration, lysine and methionine supplementation and the age of lambs on protein retention. In addition, energy balances were obtained in twenty-four of the Limousin lambs from birth up to 3 weeks of age by means of a slaughter technique. 2. For milk substitute unsupplemented with amino acids, tricaproin inclusion increased N balance slightly (P less than 0.001) when a medium-protein concentration (260 g/kg dry matter (DM] was used, in 2-week-old lambs (+4.3%) and in 5-week-old Limousin lambs (+5.3%), or very markedly when a high-protein concentration (320 g/kg DM) was used, in 2-week-old lambs (+14.5%) and in 5-week-old lambs (+18.6%). Protein requirements decreased from 300 g/kg DM in 3-week-old lambs to 270 g/kg DM in 5-week-old lambs for the control milk containing tallow-coconut oil mixture (0.67:0.33 by wt) and was increased above 300 g/kg DM at all ages in the case of experimental milk containing tallow-coconut oil-tricaproin mixture (0.33:0.33:0.33, by wt). 3. For milk containing either a medium- or a high-protein concentration and supplemented with lysine and methionine, inclusion of tricaproin increased N balance (P less than 0.01) to a similar extent (+8.5 up to +14.3%) in 1 to 2- and 3-week-old Limousin lambs. An increase in N concentration in the milk had no effect in 1- and 2-week-old lambs, but led to a decreased N balance in 3-week-old lambs. Protein requirements decreased from 310 g/kg DM in 1-week-old lambs to 190 g/kg DM in 3-week-old lambs for the milk containing tallow-coconut oil or from 300 g/kg DM in 2-week-old lambs to 210 g/kg DM in 3-week-old lambs for the milk containing tallow-coconut oil-tricaproin. 4. For the Ile de France lambs given milk supplemented with lysine and methionine, tricaproin inclusion did not alter N balance. Protein requirements decreased from 370 g/kg DM in 2-week-old lambs to 270 g/kg DM in 4-week-old lambs for milk containing both kinds of fat mixtures.(ABSTRACT TRUNCATED AT 400 WORDS)