Relationships between fatty acid status of sow plasma and that of umbilical cord, plasma and tissues of newborn piglets when sows were fed on diets containing tuna oil or soyabean oil in late pregnancy

Effect of offering maize, linseed or tuna oils throughout pregnancy and lactation on sow and piglet tissue composition and piglet performance

The effects of different dietary essential fatty acids on piglet tissue composition at birth and performance until 7 days post weaning were investigated by offering the sow diets containing (17·5 g oil per kg diet) either maize oil (MO) as a control treatment, tuna oil (TO) as a source of long chain n-3 polyunsaturated fatty acids, particularly 22:6 n-3, or a mixture of maize and linseed oils (LO) which supplied the same amount of n-3 acids as TO but in the form of 18:3 n-3. Ten sows were allocated to each treatment which was offered throughout pregnancy and lactation. Compared with MO, offering TO increased sow plasma and subcutaneous adipose tissue 22: 6 n-3 proportions whereas LO increased 18: 3 n-3 and, to a much lesser extent than TO, 22: 6 n-3. Offering TO to the sow increased the proportions of 20: 5 n-3 and 22: 6 n-3 in piglet brain and liver at birth and decreased the n-6 acids, 20: 4, 22: 4 and 22: 5. LO only increased piglet liver 20: 5 n-3 proportions but to a lesser extent than TO; however, LO also decreased the proportions of 20: 4, 22: 4 and 22: 5 n-6 in piglet tissues. Offering the pregnant sow dietary 18: 3 n-3 therefore increased deposition of 22: 6 n-3 in foetal piglet tissues to a much lesser extent than tuna oil and so it is necessary to offer the sow pre-formed 22: 6 n-3 in order to achieve maximum foetal 22: 6 n-3 deposition. By experimentally allocating piglets at birth, effects of sow nutrition during pregnancy and lactation were separated. Piglets sucking MO or TO sows were heavier than piglets sucking LO sows 7 days post weaning.

Critical review evaluating the pig as a model for human nutritional physiology

The present review examines the pig as a model for physiological studies in human subjects related to nutrient sensing, appetite regulation, gut barrier function, intestinal microbiota and nutritional neuroscience. The nutrient-sensing mechanisms regarding acids (sour), carbohydrates (sweet), glutamic acid (umami) and fatty acids are conserved between humans and pigs. In contrast, pigs show limited perception of high-intensity sweeteners and NaCl and sense a wider array of amino acids than humans. Differences on bitter taste may reflect the adaptation to ecosystems. In relation to appetite regulation, plasma concentrations of cholecystokinin and glucagon-like peptide-1 are similar in pigs and humans, while peptide YY in pigs is ten to twenty times higher and ghrelin two to five times lower than in humans. Pigs are an excellent model for human studies for vagal nerve function related to the hormonal regulation of food intake. Similarly, the study of gut barrier functions reveals conserved defence mechanisms between the two species particularly in functional permeability. However, human data are scant for some of the defence systems and nutritional programming. The pig model has been valuable for studying the changes in human microbiota following nutritional interventions. In particular, the use of human flora-associated pigs is a useful model for infants, but the long-term stability of the implanted human microbiota in pigs remains to be investigated. The similarity of the pig and human brain anatomy and development is paradigmatic. Brain explorations and therapies described in pig, when compared with available human data, highlight their value in nutritional neuroscience, particularly regarding functional neuroimaging techniques.

Effects of birth weight and maternal dietary fat source on the fatty acid profile of piglet tissue

This study aimed to investigate the effects and possible interactions of birth weight and n-3 polyunsaturated fatty acid (PUFA) supplementation of the maternal diet on the fatty acid status of different tissues of newborn piglets. These effects are of interest as both parameters have been associated with pre-weaning mortality. Sows were fed a palm oil diet or a diet containing 1% linseed, echium or fish oil from day 73 of gestation. As fish oil becomes a scarce resource, linseed and echium oil were supplemented as sustainable alternatives, adding precursor fatty acids for DHA to the diet. At birth, the lightest and heaviest male piglet per litter were killed and samples from liver, brain and muscle were taken for fatty acid analysis. Piglets that died pre-weaning had lower birth weights than piglets surviving lactation (1.27±0.04 v. 1.55±0.02 kg; P<0.001), but no effect of diet on mortality was found. Lower DHA concentrations were observed in the brain of the lighter piglets compared with their heavier littermates (9.46±0.05 v. 9.63±0.04 g DHA/100 g fatty acids; P=0.008), suggesting that the higher incidence of pre-weaning mortality in low birth weight piglets may be related to their lower brain DHA status. Adding n-3 PUFA to the sow diet could not significantly reduce this difference in DHA status, although numerically the difference in the brain DHA concentration between the piglet weight groups was smaller when fish oil was included in the sow diet. Independent of birth weight, echium or linseed oil in the sow diet increased the DHA concentration of the piglet tissues to the same extent, but the concentrations were not as high as when fish oil was fed.

Effects of dietary enrichment with a marine oil-based n-3 LCPUFA supplement in sows with predicted birth weight phenotypes on growth performance and carcass quality of offspring

Effects of a marine oil-based n-3 LCPUFA supplement (mLCPUFA) fed from weaning until the end of the next lactation to sows with a predicted low litter birth weight (LBW) phenotype on growth performance and carcass quality of litters born to these sows were studied, based on the hypothesis that LBW litters would benefit most from mLCPUFA supplementation. Sows were allocated to be fed either standard corn/soybean meal-based gestation and lactation diets (CON), or the same diets enriched with 0.5% of the mLCPUFA supplement at the expense of corn. The growth performance from birth until slaughter of the litters with the lowest average birth weight in each treatment (n=24 per treatment) is reported in this paper. At weaning, each litter was split between two nursery pens with three to six pigs per pen. At the end of the 5-week nursery period, two barrows and two gilts from each litter that had individual birth weights closest to their litter average birth weight, were moved to experimental grow-finish pens (barn A), where they were housed as two pigs per pen, sorted by sex within litter. Remaining pigs in each litter were moved to another grow-finish barn (barn B) and kept in mixed-sex pens of up to 10 littermates. After 8 weeks, one of the two pigs in each pen in barn A was relocated to the pens holding their respective littermates in barn B. The remaining barrows and gilts were individually housed in the pens in barn A until slaughter. Maternal mLCPUFA supplementation increased docosahexaenoic acid (DHA) concentration in the brain, liver and Semitendinosus muscle of stillborn pigs (P<0.01), did not affect eicosapentaenoic acid and DHA concentrations in sow serum at the end of lactation, and did not affect average daily gain, average daily feed intake or feed utilization efficiency of the offspring. BW was higher (P<0.01) in the second half of the grow-finish phase in pigs from mLCPUFA sows compared with controls in barn A, where space and competition for feed was minimal, but not barn B. Carcass quality was not affected by treatment for pigs from barn A, but maternal mLCPUFA supplementation negatively affected carcass quality in pigs from barn B. Collectively, these results suggest that nutritional supplementation of sows can have lasting effects on litter development, but that feeding mLCPUFA to sows during gestation and lactation was not effective in improving growth rates or carcass quality of LBW litters.

Transfer of conjugated linoleic acid from sows to their offspring and its impact on the fatty acid profiles of plasma, muscle, and subcutaneous fat in piglets

This experiment was conducted to determine if CLA could be transferred from sows to their offspring through the umbilical cord or milk. Eighteen pregnant Dalland sows of mixed parity were used in a completely randomized block design based on parity and BW. The sows were allotted to 1 of 3 groups and fed diets containing 0, 0.5, or 1.0% CLA during the last 50 d of gestation and throughout a 26-d lactation (n = 6). Umbilical cord blood was sampled at parturition. Colostrum and milk were collected from each sow on d 2 and 15 after farrowing. Samples of blood, backfat, and the LM were obtained from piglets at 2 and 26 d of age. Sow reproductive performance and piglet growth were not altered by CLA supplementation during the late gestation and lactation periods. The CLA supplementation of sow diets had an impact on the fatty acid profiles in colostrum and milk. Dietary CLA increased the concentrations of total SFA (linear and quadratic, P < 0.01), but reduced the total MUFA in the colostrum (linear and quadratic, P < 0.01). Although dietary CLA increased the concentrations of total SFA (quadratic, P < 0.01), it had no influence on total MUFA concentrations in the milk. In addition, feeding sows diets supplemented with CLA resulted in increases (linear and quadratic, P < 0.01) in the CLA content of plasma, backfat, and the LM in their offspring. However, trans-10, cis-12-18:2, rather than cis-9, trans-11-18:2, was detected in the umbilical cord blood, which indicates that CLA may be transported from the sow to the fetus in an isomer-specific manner.

Omega-3 fatty acids in the gravid pig uterus as affected by maternal supplementation with omega-3 fatty acids

Two experiments evaluated the ability of maternal fatty acid supplementation to alter conceptus and endometrial fatty acid composition. In Exp. 1, treatments were 1) the control, a corn-soybean meal diet; 2) flax, the control diet plus ground flax (3.75% of diet); and 3) protected fatty acids (PFA), the control plus a protected fish oil source rich in n-3 PUFA (Gromega, JBS United Inc., Sheridan, IN; 1.5% of diet). Supplements replaced equal parts of corn and soybean meal. When gilts reached 170 d of age, PG600 (PMSG and hCG, Intervet USA, Millsboro, DE) was injected to induce puberty, and dietary treatments (n = 8/treatment) were initiated. When detected in estrus, gilts were artificially inseminated. On d 40 to 43 of gestation, 7 gilts in the control treatment, 8 gilts in the PFA treatment, and 5 gilts in the flax treatment were pregnant and were slaughtered. Compared with the control treatment, the flax treatment tended to increase eicosapentaenoic acid (EPA: C20:5n-3) in fetuses (0.14 vs. 0.25 +/- 0.03 mg/g of dry tissue; P = 0.055), whereas gilts receiving PFA had more (P < 0.05) docosahexaenoic acid (DHA: C22:6n-3) in their fetuses (5.23 vs. 4.04 +/- 0.078 mg/g) compared with gilts fed the control diet. Both the flax and PFA diets increased (P < 0.05) DHA (0.60, 0.82, and 0.85 +/- 0.078 mg/g for the control, flax, and PFA diet, respectively) in the chorioallantois. In the endometrium, EPA and docosapentaenoic acid (C22:5n-3) were increased by the flax diet (P < 0.001; P < 0.05), whereas gilts receiving PFA had increased DHA (P < 0.001). The flax diet selectively increased EPA, and the PFA diet selectively increased DHA in the fetus and endometrium. In Exp. 2, gilts were fed diets containing PFA (1.5%) or a control diet beginning at approximately 170 of age (n = 13/treatment). A blood sample was collected after 30 d of treatment, and gilts were artificially inseminated when they were approximately 205 d old. Conceptus and endometrial samples were collected on d 11 to 19 of pregnancy. Plasma samples indicated that PFA increased (P < 0.005) circulating concentrations of EPA and DHA. Endometrial EPA was increased (P < 0.001) for gilts fed the PFA diet. In extraembryonic tissues, PFA more than doubled (P < 0.001) the EPA (0.13 vs. 0.32 +/- 0.013 mg/g) and DHA (0.39 vs. 0.85 +/- 0.05 mg/g). In embryonic tissue on d 19, DHA was increased (P < 0.05) by PFA (0.20 vs. 0.30 +/- 0.023 mg/g). Supplementing n-3 PUFA, beginning 30 d before breeding, affected endometrial, conceptus, and fetal fatty acid composition in early pregnancy. Dynamic day effects in fatty acid composition indicate this may be a critical period for maternal fatty acid resources to affect conceptus development and survival.

In utero and postnatal exposure to long chain (n-3) PUFA enhances intestinal glucose absorption and energy stores in weanling pigs

The aim of this research was to determine whether feeding gestating and lactating sows (n-3) PUFA [eicosapentaenoic acid (EPA) and/or docosahexenoic acid (DHA)] or coconut fat (saturated fat) influences ex vivo glucose absorption in the proximal jejunum and glucose and glycogen concentration of liver and muscle of their offspring at weaning. Sows were fed 1 of 4 diets for 150 d, which included the entire gestation and lactation periods. The diets consisted of basal corn/soybean meal (CONT), CONT + protected EPA and DHA-rich fish oil (PFO), CONT + DHA Gold fat (DHAGF), and CONT + coconut fat (COCO). All tissues were collected from piglets (n = 4 per treatment) following a 24-h period of food deprivation, which was initiated at weaning. Proximal jejunum samples were mounted in modified Ussing chambers for transport determinations. Relative to the CONT (7 muA/cm(2)), active glucose transport was greater (P = 0.013) in piglets from sows fed the PFO (30 microA/cm(2)) and DHAGF (40 microA/cm(2)) diets, but not the COCO diet (19 microA/cm(2); pooled SEM = 5). Likewise, jejunum expression of glucose transporter 2 and sodium glucose transporter 1 protein tended (P < 0.10) to be greater in piglets from dams fed the PFO and DHAGF diets, as did AMP-activated protein kinase activity. Piglets' muscle glycogen was greater than in CONT (34 +/- 5.2 mg/g wet tissue) only in piglets from dams fed the DHAGF (46 +/- 5.2 mg/g wet tissue; P < 0.05). These results indicate that (n-3) PUFA, particularly DHA, improves intestinal glucose absorption and muscle glycogen concentrations in newly weaned pigs. These findings may also have important implications for human mothers and infants.

Polyunsaturated fatty acid supplementation during pregnancy alters neonatal behavior in sheep

The objectives of the study were to determine whether supplementation of pregnant ewes with long-chain (n-3) fatty acids present in fish oil, in combination with dietary vitamin E, would alter neonatal behavior in sheep. Twin- (n=36) and triplet- (n=12) bearing ewes were allocated at d 103 of gestation to 1 of 4 dietary treatments containing 1 of 2 fat sources [Megalac, a calcium soap of palm fatty acid distillate or a fish oil mixture, high in 20:5(n-3) and 22:6(n-3)] and 1 of 2 dietary vitamin E concentrations (50 or 500 mg/kg) in a 2 x 2 factorial design. Feeding fish oil increased gestation length by 2 d and increased the proportion of 22:6(n-3) within neonatal plasma by 5.1-fold and brain by 10%, whereas brain 20:5(n-3) was increased 5-fold. Supranutritional dietary vitamin E concentrations decreased the latency of lambs to stand in ewes fed fish oil but not Megalac, whereas latency to suckle was decreased from 43 to 34 min by fish oil supplementation. Supplementation with fish oil also substantially decreased the secretion rate (mL/h) of colostrum and the yield (g/h) of fat and protein. We conclude that supplementation of ewes with fish oil decreases the latency to suckle, increases gestation length and the 22:6(n-3):20:4(n-6) ratio in the neonatal brain, and may improve lamb survival rate. However, further work is required to determine how to mitigate the negative effects of fish oil on colostrum production.

Dietary α-linolenic acid increases the n−3 PUFA content of sow's milk and the tissues of the suckling piglet

alpha-Linolenic acid (18:3n-3) is a precursor to DHA (22:6n-3), which is essential for normal growth and development in the infant. This study was undertaken to assess how a raised 18:3n-3 intake in sows affects the n-3 PUFA content of the suckling piglet. Sows consumed a high-18:3n-3 or control diet (n-3 PUFA/n-6 PUFA, 0.5 vs. 0.05, respectively) for 10 d prior to parturition and for 14 d postpartum. Piglets suckled from their mothers until 14 d of age, when they were sacrificed. Sows consuming the high-18:3n-3 diet had 141% more 18:3n-3 and 86% more 22:6n-3 in their milk compared to control sows. There was no difference in the proximate composition of the piglets. The n-3/n-6 PUFA ratio was 82% higher in the milk of sows consuming the high-18:3n-3 diet compared to controls. Piglets suckling from sows consuming the high-18:3n-3 diet had 423% more 18:3n-3 in the carcass as well as a 460% higher n-3/n-6 PUFA ratio than controls. The piglets suckling from sows consuming the high-18:3n-3 diet had 333% more 18:3n-3 and 54% more 22:6n-3 in the liver, as well as a 114% higher n-3/n-6 ratio than control piglets. Piglets suckling from sows consuming a high-18:3n-3 diet also had 24% more 22:6n-3 and a 33% higher n-3/n-6 ratio in the brain compared to control piglets. A high 18:3n-3 intake in the sow increases not only the 18:3n-3 but also the 22:6n-3 content of sow's milk and the tissues of the suckling piglet.

Changes in piglet tissue composition at birth in response to increasing maternal intake of long-chain n-3 polyunsaturated fatty acids are non-linear

Addition of marine oils containing long-chain n-3 polyunsaturated fatty acids to the diet of pregnant sows may reduce piglet mortality. In previous experiments, when marine oils have been fed to pregnant sows, improvements in piglet tissue 22 : 6n-3 status have been accompanied by potentially undesirable decreases in 20 : 4n-6. The objective of the present experiment was to establish an amount of dietary salmon oil which would enhance piglet 22 : 6n-3 status while minimising reductions in 20 : 4n-6. Twenty-four pregnant multiparous sows were used in the experiment which began on day 60 of pregnancy (gestation length 115 d). To give four diets, salmon oil was added in increasing amounts (0, 5, 10 and 20 g/kg diet) to a basal diet; the diets were made isoenergetic by adding palm oil to each diet to give a total of 20 g oil/kg diet. Diets were offered to the sows in fixed amounts (2.5 kg/d) until parturition. Piglet tissue samples (brain, liver and retina) were obtained at birth before consumption of colostrum. The greatest increase in piglet tissue 22 : 6n-3 proportions occurred between 0 and 5 g salmon oil/kg diet, with only small increases between 10 and 20 g salmon oil/kg diet. In contrast, tissue 20 : 4n-6 proportions declined progressively as the amount of salmon oil fed to the sow increased. In brain, the change in the value 22 : 6n-3/22 : 5n-6 was greatest between 0 and 5 g salmon oil/kg diet, whereas in liver the value increased linearly with added salmon oil. In addition, piglet brain weight (g/kg live weight) increased to a maximum at 10 g salmon oil/kg diet. The optimum amount of supplementary salmon oil in the current experiment, defined as that which gave the greatest response in brain 22 : 6n-3 proportions with minimum reduction in 20 : 4n-6,was 10 g salmon oil/kg diet. This corresponds to an intake of approximately 2.4 g 20 : 5n-3 plus 3.6 g 22 : 6n-3/d or 0.6 % digestible energy.

Feeding tuna oil to the sow at different times during pregnancy has different effects on piglet long-chain polyunsaturated fatty acid composition at birth and subsequent growth

In an attempt to prevent decreases in piglet 20 : 4n-6 status at birth while increasing 22 : 6n-3 status, multiparous sows (eight per treatment) were allocated to one of three different treatments: a basal diet fed from day 63 of pregnancy to term; basal diet supplemented with tuna oil (17.5 g/kg) from day 63 to day 91 and then basal diet alone from day 92 to term; basal diet alone from day 63 to day 91 and then basal diet supplemented with tuna oil from day 92 to term. Tuna oil supplementation increased mainly 22 : 6n-3 intake. Supplementation with tuna oil between day 92 and term increased 22 : 6n-3 to a greater extent in all piglet tissues (brain, liver, retina and the remaining carcass) at birth than supplementation with tuna oil between days 63 and 91. However, while piglet 20 : 4n-6 decreased to a greater extent in liver and carcass when diets were supplemented with tuna oil between days 92 and term than between days 63 and 91, in the brain and retina, the reverse was true; 20 : 4n-6 was decreased to a greater extent between days 63 and 91 than between 92 and term. The effect of pregnancy nutrition on the growth of piglets until 7 d postweaning (35 d of age) was assessed after removing any residual effects of pregnancy treatment by cross-fostering some piglets at birth. Piglets, the diets of whose dams had been supplemented with tuna oil during pregnancy, grew faster during the first 35 d of life than the progeny of sows fed only the basal diet. Feeding tuna oil to sows at different times during pregnancy therefore did not prevent decreases in piglet 20 : 4n-6 status at birth, but did suggest that changes in piglet brain 20 : 4n-6 status between days 63 and 91 of pregnancy were not reversible by later nutrition. Supplementing the diet of the pregnant sow with tuna oil had beneficial effects on postnatal piglet growth.