Charlotte Lauridsen

Dietary vitamin E: Quality and storage stability of pork and poultry

Lipid oxidation is one of the primary processes of quality deterioration in meat and meat products. The changes in quality are manifested by adverse changes in flavour, colour, texture, and nutritive value and by the possible production of toxic compounds. Dietary supplementation of vitamin E above requirement levels has been found to be effective in reducing lipid oxidation in meat and meat products. This review focuses on the deposition and antioxidative effects of muscle vitamin E and how supra-nutritional vitamin E supplementation influences lipid oxidation, colour, water-holding capacity and cholesterol oxidation in pig and poultry meat. Furthermore, the interactions between muscle vitamin E with processing, packaging and storage conditions are taken into consideration.

Influence of dietary conjugated linoleic acid (CLA) and age at slaughtering on performance, slaughter- and meat quality, lipoproteins, and tissue deposition of CLA in barrows

To assess the effects of dietary conjugated linoleic acid (CLA) on performance, slaughter and meat quality, 100 Danish barrows were fed diets containing 0.5% sunflower oil (control) and 0.5% CLA from 40 kg live weight until slaughter at either 100 or 130 kg live weight. Plasma total cholesterol (P=0.006) and HDL-cholesterol (P=0.021) was reduced, and plasma FFA-concentration increased (P=0.06) in pigs fed CLA. CLA supplementation improved (P=0.01) the feed utilisation by 4.7% and 4.3% for pigs slaughtered at 100 and 130 kg, respectively. Daily gain tended (P=0.06) to increase with the CLA-treatment (1.236 versus 1.194 kg for CLA- and control, respectively). Dietary treatments had no effects on slaughter- (meat percentage and backfat thickness) and meat quality responses (pH, temperature and water holding capacity). CLA tended (P=0.09) to reduce the intramuscular cholesterol, but had no influence on the total content of intramuscular fat.

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.

Neonatal piglet survival: impact of sow nutrition around parturition on fetal glycogen deposition and production and composition of colostrum and transient milk.

Piglet survival is a major problem, especially during the first 3 days after birth. Piglets are born deficient of energy, but at the same time they have a very high energy requirement because of high physical activity, high need for thermoregulation (because of their lean body with low insulation) and high heat production in muscle tissues. To be able to survive, newborn piglets may rely upon three different sources of energy, namely, glycogen, colostrum and transient milk, which orchestrate to cover their energy requirements. Piglets are born with limited amounts of energy in glycogen depots in the liver and muscle tissues and these depots are sufficient for normal activity for ∼16 h. Intake and oxidation of fat and lactose from colostrum must supply sufficient amount of energy to cover at least another 18 h until transient milk becomes available in the sow udder ∼34 h after the first piglet is born. Selection for large litters during the last two decades has challenged piglets even further during the critical neonatal phase because the selection programs indirectly decreased birth weight of piglets and because increased litter size has increased the competition between littermates. Different attempts have been made to increase the short-term survival of piglets, that is, survival until day 3 of lactation, by focusing on improving transfer of vital maternal energy to the offspring, either in utero or via mammary secretions. Thus, the present review addresses how sow nutrition in late gestation may favor survival of newborn piglets by increasing glycogen depots, improving colostrum yield or colostrum composition, or by increasing production of transient milk.

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.

Effect of silver nanoparticles on growth performance, metabolism and microbial profile of broiler chickens

This study evaluated the potential of silver nanoparticles (AgNano) as an antimicrobial growth-promoting supplement for broiler chickens. One hundred forty-four seven-day-old broiler chicks were distributed randomly to AgNano treatments at 0, 10 and 20 mg/kg (Control, Group AgNano10, and Group AgNano20, respectively) provided via the drinking water from day 7 to 36 post-hatching. Body weight and feed consumption were measured weekly. In addition, balance and respiration experiments were carried out to determine nitrogen (N) utilisation and energy retention. At days 22 and 36, blood samples and intestinal content were collected to evaluate the effects of AgNano on plasma concentration of immunoglobulins and the intestinal microflora, repectively. The provision of water solutions containing different concentrations of AgNano had no effect on postnatal growth performance and the energy metabolism of broiler chickens. However, in Group AgNano10 N intake (p = 0.05) and retention (p = 0.03) was increased, but N excretion and efficiency of utilisation was not affected. The populations of bacteria in the intestinal samples were not affected by AgNano supplementation. The concentration of immunoglobulin (IgG) in the blood plasma of broilers supplemented with AgNano decreased at day 36 (p = 0.012). The results demonstrated that AgNano affects N utilisation and plasma IgG concentration; however, it does not influence the microbial populations in the digestive tract, the energy metabolism and growth performance of chickens.

Dietary fat source affects metabolism of fatty acids in pigs as evaluated by altered expression of lipogenic genes in liver and adipose tissues

Little is known about pig gene expressions related to dietary fatty acids (FAs) and most work have been conducted in rodents. The aim of this study was to investigate how dietary fats regulate fat metabolism of pigs in different tissues. Fifty-six crossbred gilts (62 ± 5.2 kg BW) were fed one of seven dietary treatments (eight animals per treatment): a semi-synthetic diet containing a very low level of fat (no fat (NF)) and six fat-supplemented diets (ca. 10%) based on barley and soybean meal. The supplemental fat sources were tallow (T), high-oleic sunflower oil (HOSF), sunflower oil (SFO), linseed oil (LO), blend (FB) (55% T, 35% SFO and 10% LO) and fish oil (FO) blend (40% FO and 60% LO). Pigs were slaughtered at 100 kg BW and autopsies from liver, adipose tissue and muscle semimembranousus were collected for qPCR. The messenger ribonucleic acid (mRNA) abundances of genes related to lipogenesis were modified due to dietary treatments in both liver (sterol regulatory element-binding protein-1 (SREBP-1), acetyl CoA carboxylase (ACACA) and stearoyl CoA desaturase (SCD)) and adipose tissue (fatty acid synthase (FASN), ACACA and SCD), but were not affected in semimembranousus muscle. In the liver, the mRNA abundances of genes encoding lipogenic enzymes were highest in pigs fed HOSF and lowest in pigs fed FO. In adipose tissue, the mRNA abundances were highest in pigs fed the NF diet and lowest in pigs fed T. The study demonstrated that dietary FAs stimulate lipogenic enzyme gene expression differently in liver, fat and muscles tissues.

Effects of nutrient supply, plasma metabolites, and nutritional status of sows during transition on performance in the next lactation1

The aim of the present study was to evaluate the effects of nutrient supply, plasma metabolites, and nutritional status of sows during the transition from gestation to lactation on performance of piglets during the colostral period and throughout lactation. Forty second-parity sows were fed 1 of 4 gestation diets containing a different quantity of dietary fiber (171 to 404 g/kg of DM) from mating until d 108 of gestation. From d 108 of gestation until weaning (d 28 of lactation), sows were fed 1 of 5 lactation diets with a different quantity of dietary fat [3 or 8% with different proportions of medium- (MCFA) and long-chain fatty acids (LCFA)]. Blood was obtained by jugular venipuncture on d 108 and 112 of gestation and on d 1 of lactation, and concentrations of plasma glucose, NEFA, lactate, acetate, propionate, butyrate, and fatty acids were analyzed. Piglet growth and mortality were noted throughout lactation. Piglet mortality during the colostral period (0 to 24 h) was affected by the lactation diets and was positively related to sow backfat (d 108) and plasma lactate (d 112) and negatively related to mean piglet birth weight (P < 0.05). Mean piglet live BW gain (LWG) was recorded in the periods 0 to 24 h, 7 to 10 d, 14 to 17 d, and 17 to 28 d relative to parturition as indirect measures of colostrum yield (0 to 24 h), milk yield in early lactation (d 7 to 10), and at peak lactation (d 14 to 17 and d 17 to 28). Effects of gestation and lactation diets on studied sow traits were tested on selected days during the transition period and the next lactation, and tested statistically on separate days. The LWG in the colostral period was positively correlated with mean piglet birth weight (P < 0.001), plasma concentrations of propionate and MCFA (P < 0.05), and plasma acetate and butyrate (P < 0.1) on d 1 of lactation. The LWG in early lactation was inversely correlated with plasma lactate on d 108 (P < 0.05), plasma glucose on d 112, and backfat thickness on d 108 (P < 0.10). The LWG at peak lactation was positively correlated with MCFA intake of the sow on d 113 to 115 and backfat thickness on d 108 during the transition, and negatively correlated with intake of LCFA and ME intake on d 108 to 112 (P < 0.05). In conclusion, feeding and body condition of sows during the transition from gestation to lactation is important for neonatal piglet survival, lactation performance of sows, and piglet growth during the next lactation.