Søren Krogh Jensen

Enteral feeding induces diet-dependent mucosal dysfunction, bacterial proliferation, and necrotizing enterocolitis in preterm pigs on parenteral nutrition

Preterm neonates have an immature gut and metabolism and may benefit from total parenteral nutrition (TPN) before enteral food is introduced. Conversely, delayed enteral feeding may inhibit gut maturation and sensitize to necrotizing enterocolitis (NEC). Intestinal mass and NEC lesions were first recorded in preterm pigs fed enterally (porcine colostrum, bovine colostrum, or formula for 20-40 h), with or without a preceding 2- to 3-day TPN period (n = 435). Mucosal mass increased during TPN and further after enteral feeding to reach an intestinal mass similar to that in enterally fed pigs without TPN (+60-80% relative to birth). NEC developed only after enteral feeding but more often after a preceding TPN period for both sows colostrum (26 vs. 5%) and formula (62 vs. 39%, both P < 0.001, n = 43-170). Further studies in 3-day-old TPN pigs fed enterally showed that formula feeding decreased villus height and nutrient digestive capacity and increased luminal lactic acid and NEC lesions, compared with colostrum (bovine or porcine, P < 0.05). Mucosal microbial diversity increased with enteral feeding, and Clostridium perfringens density was related to NEC severity. Formula feeding decreased plasma arginine, citrulline, ornithine, and tissue antioxidants, whereas tissue nitric oxide synthetase and gut permeability increased, relative to colostrum (all P < 0.05). In conclusion, enteral feeding is associated with gut dysfunction, microbial imbalance, and NEC in preterm pigs, especially in pigs fed formula after TPN. Conversely, colostrum milk diets improve gut maturation and NEC resistance in preterm pigs subjected to a few days of TPN after birth.

Quantitative secretion and maximal secretion capacity of retinol, β-carotene and α-tocopherol into cows' milk

Summary. Changes in the contents of retinol, a-tocopherol and b-carotene in plasma, milk and milk fat from 38 Holstein‐Friesian cows were followed during their first lactation, and the quantitative and kinetic relationships for secretion of a-tocopherol and b-carotene from blood into milk were determined. The cows were assigned to three groups such that all cows in the same group had the same sire. Milk yield and milk fat content diered with stage of lactation, but not according to sire. The plasma concentrations of retinol, a-tocopherol and b-carotene diered with stage of lactation; in addition, retinol and b-carotene concentration also diered according to sire. The concentrations of all three vitamins in milk and milk fat diered according to sire and stage of lactation. Furthermore, the total secretion of retinol, a-tocopherol and b-carotene into milk (expressed as mg}d) diered with sire and stage of lactation. The quantitative secretion of a-tocopherol and b-carotene from blood into milk followed Michaelis‐Menten kinetics for active transport across membranes. Values of maximum secretory capacity V max and the half-rate constant K m for both a-tocopherol and b-carotene varied according to sire. Overall means for V max for a-tocopherol and b-carotene were 32‐4 and 2‐ 5m g}d. Thus, the daily secretion of a-tocopherol and b-carotene is limited in quantity, and is independent of the yields of milk and milk fat. It follows that continuing breeding and management systems that focus solely on increasing milk and milk fat yield will result in a steady dilution in the milk fat of these vitamins and antioxidants important for the immune defence of the cows and oxidative stability of milk products. The genetic variation found oers the possibility of utilizing these variations in breeding systems.

Tocopherols, retinol, β-carotene and fatty acids in fat globule membrane and fat globule core in cows' milk

Milk fat globule membranes (MFGM) were isolated from milk from cows injected intraperitoneally with dl-alpha-tocopherol acetate. The fatty acid composition and content, and the contents of tocopherols, retinol and beta-carotene were determined and compared with the composition and content in the original cream sample. Intraperitoneal injection of 10 g dl-alpha-tocopherol acetate elevated the alpha-tocopherol content in the milk fat from 13-30 to 50-70 micrograms alpha-tocopherol/g milk fat 2-3 d after injection. The increase depended on the alpha-tocopherol status of the cow prior to injection. The concentrations of retinol and beta-carotene in the milk fat were unchanged after the alpha-tocopherol injections. MFGM fatty acids made up 18-27 g/kg total fatty acids in the milk fat. However, the proportions of monounsaturated and polyunsaturated fatty acids were higher in MFGM than in total milk fat, while the proportion of saturated fatty acids was lower in MFGM (P < 0.001). Thus, the long-chain polyunsaturated fatty acids in MFGM constituted approximately 40-70 g/kg total milk fat. alpha-Tocopherol was the only fat-soluble vitamin detected in MFGM; gamma-tocopherol, retinol and beta-carotene were detected only in the cream. A significant relationship between alpha-tocopherol contents in cream and MFGM was found: (alpha-tocopherol in MFGM fatty acids) = -1652 x (1/ln(alpha-tocopherol in cream fatty acids)3) + 97 (r = 0.857, P < 0.001) when the contents of alpha-tocopherol were expressed as microgram/g fatty acid. According to this equation the upper limit for incorporation of alpha-tocopherol into MFGM is 97 +/- 5 micrograms/g MFGM fatty acids. Thus, under normal farming conditions the alpha-tocopherol content will be highest in MFGM. However, in cream with an alpha-tocopherol concentration < 15 micrograms/g cream fatty acids the concentration in MFGM will be lower and furthermore will decrease rapidly. The possible importance of this relationship in relation to the oxidation of milk fat is discussed.

Quantitative Determination of Bile Salt Hydrolase Activity in Bacteria Isolated from the Small Intestine of Chickens

ABSTRACT A quantitative assay based on high-performance liquid chromatography analysis of bile salts and bacterial protein determination was established for investigating bile salt hydrolase (BSH) activity in bacteria isolated from the small intestine of chickens. Bacteria were isolated using various media and were subsequently grouped according to cell morphology, fermentation profile, and 16S ribosomal DNA sequence. Representative isolates from each bacterial group were assayed for BSH activity. The isolates differed in BSH activity with respect to the state of growth and preculturing with and without taurochenodeoxycholate. The highest levels of BSH activity were found with Enterococcus faecium and Clostridium perfringens.

Formula-feeding reduces lactose digestive capacity in neonatal pigs

The intestine of newborn pigs develops rapidly during the first days postpartum. We investigated if feeding milk replacer (infant formula) as an alternative to colostrum has compromising effects on nutrient digestive function in the neonatal period. Nineteen piglets born at term were assigned to one of four treatments: (1) newborn controls; (2) natural suckling for 24 h; (3) tube-fed formula for 24 h; (4) tube-fed porcine colostrum for 24 h. All three fed groups showed significant increases in small-intestinal and colonic weights, villous heights and widths, maltase and aminopeptidase A activities, and decreases in dipeptidylpeptidase IV activity, relative to newborn pigs. Following oral boluses of mannitol, lactose or galactose, formula-fed pigs showed significantly reduced plasma levels of mannitol and galactose compared with colostrum-fed pigs. Activity of intestinal inducible NO synthase and plasma levels of cortisol were significantly increased, whereas intestinal constitutive NO synthase and alpha-tocopherol were decreased in formula-fed pigs compared with colostrum-fed pigs. Although formula-fed pigs only showed minor clinical signs of intestinal dysfunction and showed similar intestinal trophic responses just after birth, as those fed colostrum, lactose digestive capacity was markedly reduced. We conclude that formula-feeding may exert detrimental effects on intestinal function in neonates. Formula-induced subclinical malfunction of the gut in pigs born at term was associated with altered NO synthase activity and antioxidative capacity.

a-Tocopherol Stereoisomers

Vitamin E comprises a group of compounds possessing vitamin E activity. alpha-Tocopherol is the compound demonstrating the highest vitamin E activity, which is available both in its natural form as RRR-alpha-tocopherol isolated from plant sources, but more common as synthetically manufactured all-rac-alpha-tocopherol. Synthetic all-rac-alpha-tocopherol consists of a racemic mixture of all eight possible stereoisomers. Assessing the correct biological activity in form of bioavailability and biopotency has been a great challenge during many years as it is difficult to measure clinical endpoints in larger animals than rats and poultry. Thus, the biological effects in focus are resorption of fetuses, testicular degeneration, muscle dystrophy, anemia, encephalomalacia, and in recent years the influence of vitamin E on the immune system are the most important clinical markers of interest. For humans and animals, only different biomarkers or surrogate markers of bioactivity have been measured. In studies with rats, a good consistency between the classical resorption-gestation test and the bioavailability of the individual stereoisomers in fluids and tissues has been shown. For humans and other animals, only different biomarkers or surrogate markers of bioactivity have been measured, and due to the lack of good biological markers for bioactivities, bioavailability is often used as one of the surrogate markers for bioactivities with those limitations this must give. Therefore, a relatively simple analytical method, which allows analysis of the individual stereoisomers of alpha-tocopherol, is an important tool in order to quantify relative bioavailability of the individual stereoisomers. The analytical method presented here allows the quantification of total tocopherol content and composition by normal phase HPLC and subsequent separation of the stereoisomers of alpha-tocopherol as methyl ethers by chiral HPLC. Using this method, the alpha-tocopherol stereoisomers are separated into five peaks. The first peak consists of the four 2S isomers (SSS-, SSR-, SRR-, SRS-), the second peak consists of RSS-, the third peak consists of RRS-, the fourth peak consists of RRR-, and the fifth peak consists of RSR-alpha-tocopherol. The discussion on the bioavailability of RRR- and all-rac-alpha-tocopheryl acetate has primarily been based on human and animal studies using deuterium-labeled forms, whereby a higher biopotency of 2:1 (of RRR: all-rac) has been demonstrated, differing from the accepted biopotency ratio of 1.36:1. In agreement with previous studies, the 2S-forms exert very little importance for the vitamin E activity due to their limited bioavailability. We find notable differences between animal species with regard to the biodiscrimination between the 2R-forms. Especially, cows preferentially transfer RRR- alpha-tocopherol into the milk and blood system. The distribution of the stereoisomer forms varies from tissue to tissue, and in some cases, higher levels of the synthetic 2R-forms than of the RRR-form are obtained, for example, for rats. However, the biodiscrimination of the stereoisomers forms is influenced by other factors such as age, dietary levels, and time after dosage. More focus should be given on the bioactivity of the individual 2R-forms rather than just the comparison between RRR- and all-rac-alpha-tocopheryl acetate.

α-Tocopherol concentration and stereoisomer composition in plasma and milk from dairy cows fed natural or synthetic vitamin E around calving

The aim of this study was to compare the effects of supplementing dairy cows with 1000 IU/day of all-rac-alpha-tocopheryl acetate (SynAc), RRR-alpha-tocopheryl acetate (NatAc), or RRR-alpha-tocopherol (NatAlc), from approximately 3 weeks before estimated calving until 2 weeks after calving, on the concentration of alpha-tocopherol and its stereoisomers (RRR-, RSS-, RRS-, RSR- and the four 2S-forms of alpha-tocopherol) in blood and milk. An unsupplemented group was included as control. Blood samples were collected at 3, 2 and 1 weeks before estimated calving, at calving, and 3, 7 and 14 days after calving, while milk samples were taken twice within 24 h after calving and at 7 and 14 days in milk. Overall, time and treatment had significant effects on plasma alpha-tocopherol with higher concentrations in NatAc than in the other groups. In addition, SynAc had higher concentrations than Control, and NatAlc tended to be higher than Control. The lowest plasma concentrations were observed at calving and 3 days after calving. Independent of treatment, the concentration was higher in colostrum than in milk day 7 and 14 after calving. Analyses of the stereoisomer distribution in plasma and milk showed that, irrespective of dietary treatment, RRR-alpha-tocopherol was the most predominant form, constituting more than 86%, whereas the remaining part of alpha-tocopherol was made up by the three synthetic 2R isomers, while the 2S isomers only contributed less than 1% of the total alpha-tocopherol. In control cows and cows supplemented with natural vitamin E, the proportion of RRR-alpha-tocopherol in plasma and milk constituted more than 98% of the total alpha-tocopherol. In conclusion, the results indicate that daily oral supplementation of dairy cows with RRR-alpha-tocopheryl acetate gives the highest blood concentrations of alpha-tocopherol in the periparturient period. Analyses of the distribution of the individual stereoisomers of alpha-tocopherol further indicate that the bioavailability of RRR-alpha-tocopherol relative to synthetic stereoisomers in cattle is considerably higher than officially accepted until now.

Hydrolysis of tocopheryl and retinyl esters by porcine carboxyl ester hydrolase is affected by their carboxylate moiety and bile acids

The objective of this study was to examine the in vitro hydrolysis of vitamin E esters (alpha-tocopheryl acetate, alpha-tocopheryl succinate and alpha-tocopheryl nicotinate) by pancreatic carboxyl ester hydrolase (CEH) at the concurrent presence of different bile acids at different concentrations. The assay was performed by measuring the amount of alpha-tocopherol released by porcine pancreatic juice upon addition to different solutions of alpha-tocopheryl esters, which were dispersed in bile acid mixed micelles at 37 degrees C, pH 7.4. The CEH activity was 10 U in the final assay, and the optimal concentration of cholate in this in vitro-system was determined to 30 mM for the hydrolysis of alpha-tocopheryl acetate. The hydrolysis of alpha-tocopheryl esters required presence of pancreatic juice and bile acids, and the results showed furthermore that the ability of pancreatic CEH towards hydrolysis of different alpha-tocopheryl esters increased with increasing lipophility, irrespective of the type or concentration of bile acid present in the assay. Likewise, retinyl palmitate was hydrolyzed at a faster rate than retinyl acetate. The structure of the bile acid influenced the rate of hydrolysis. Thus, cholate followed by glycodeoxy- and glycochenodeoxycholate were the most effective activators of CEH among the bile acids tested in this assay. The presence of gamma-tocopherol or all-trans-retinyl acetate in the assay showed a non-competitive inhibition of the hydrolysis rate of alpha-tocopheryl acetate.

The Influence of Rapeseed Oil on Digestibility, Energy Metabolism and Tissue Fatty Acid Composition in Pigs

Abstract The influence of rapeseed oil on digestibility, energy metabolism and tissue composition in growing pigs was determined. Rapeseed oil (0, 4, 8 and 16%) was added to a soyabean meal and barley basal diet. Essential amino acids relative to net energy (NE) were kept constant by adjusting with crystalline amino acids. Rapeseed oil has a high content of the unsaturated fatty acids 18:1n-9, 18:2n-6 and 18:3n-3, and is rich in natural tocopherols, which act as antioxidants. The apparent protein digestibility was enhanced with increasing levels of rapeseed oil. Improving the ratio of essential to non-essential amino acids decreased nitrogen execretion in faeces and urine by 21% and 26%, respectively. The amount of digestible fat increased from 29 to 218 g day−1 from the control diet to the diet with 16% rapeseed oil, resulting in a fat retention of 195 to 213 g day−1. This demonstrates the ability of pig for de novo synthesis of fatty acids. The digestibility of the rapeseed oil was high (92.7), and the ...

Reproductive performance and bone status markers of gilts and lactating sows supplemented with two different forms of vitamin D.

In swine nutrition, little is known about the vitamin D requirements for reproductive processes and bone health. Consequently, the vitamin D recommendation for sows during gestation and lactation is not based on scientific reports. The current study was undertaken to obtain information on the dose-response pattern of 2 vitamin D sources, the commonly used cholecalciferol, called vitamin D(3), and a newly developed Hy.D product (25-hydroxycholecalciferol). In Exp. 1, a total of 160 gilts were randomly assigned from the first estrus until d 28 of gestation to dietary treatments containing 4 concentrations of 1 of the 2 different vitamin D sources [200, 800, 1,400, and 2,000 IU/kg of vitamin D from cholecalciferol or corresponding doses of 5, 20, 35, and 50 microg/kg of feed from 25(OH)D(3) (Hy.D)]. In a concurrent experiment, the same 8 dietary treatments were provided to 160 multiparous sows from the first day of mating until weaning. Plasma concentrations of 25(OH)D(3) were influenced by a dose x form interaction (P < 0.001); furthermore, plasma 25(OH)D(3) concentrations were influenced by the lactation state of the sows. Irrespective of the dietary dose and form of vitamin D provided to the sows, very little vitamin D was transferred to the progeny. Reproductive performance was not influenced by dietary vitamin D treatments, except for a decreased number of stillborn piglets (P = 0.03, SE = 0.40) with the larger doses of vitamin D (1,400 and 2,000 IU of vitamin D, resulting in 1.17 and 1.13 stillborn piglets per litter, respectively) compared with the smaller doses of vitamin D (200 and 800 IU of vitamin D, resulting in 1.98 and 1.99 stillborn piglets per litter, respectively). In the gilt trial, the ultimate strength of the bones (P = 0.01) and their content of ash (P = 0.02) were greater when vitamin D(3) was supplemented in doses larger than 800 IU, compared with the same amount of Hy.D supplementation. In the sow experiment, lactation day (P < 0.001), rather than dietary vitamin D, influenced the concentrations of osteocalcin and Ca as well as the activities of total alkaline phosphatase and bone alkaline phosphatase in plasma. Age of the suckling piglets affected their plasma bone health markers. In conclusion, at doses greater than 200 IU, Hy.D was more bioavailable than vitamin D(3) and, as such, could be considered an equivalent or even more advantageous source of vitamin D. In addition, a dietary dose of approximately 1,400 IU of vitamin D is recommended for reproducing swine. Irrespective of the dietary dose and form of vitamin D provided to the sows, very little vitamin D was transferred to the progeny.