Effects of dietary energy and lysine intake during late gestation and lactation on blood metabolites, hormones, milk composition and reproductive performance in multiparous sows

Effect of Dietary Energy Level during Late Gestation on Mineral Contents in Colostrum, Milk, and Plasma of Lactating Jennies

This study investigated the effects of dietary energy levels during late gestation on mineral content in the plasma, colostrum, and milk of jennies postpartum. Twenty-four pregnant multiparous DeZhou jennies, aged 6.0  ±  0.1 years, with a body weight of 292  ±  33 kg, an average parity number of 2.7  ±  0.1, and similar expected dates of confinement (74  ±  4 days), were randomly allocated to three groups and fed three diets: high energy (12.54 MJ/kg, HE), medium energy (12.03 MJ/kg, ME), and low energy (11.39 MJ/kg, LE). Blood samples were collected from the jugular vein of each jenny at time points of 0 h, 24 h, 48 h, 5 d, 7 d, and 14 d after parturition. Additionally, milk samples were collected through manual milking, and an analysis of the mineral content was conducted. The results showed that compared with HE, both ME and LE significantly increased the levels of calcium (Ca), phosphorus (P), zinc (Zn), selenium (Se), molybdenum (Mo), and cobalt (Co) in the plasma and Ca, P, magnesium (Mg), copper (Cu), manganese (Mn), Zn, selenium (Se), molybdenum (Mo), and Co in the milk of jennies postpartum (p < 0.05); ME also increased the levels of potassium (K), iron (Fe), and Mn in plasma and K and Fe in milk (p < 0.05). The levels of Ca, K, Mg, P, Fe, Cu, Mn, Co, Se, Zn, and Mo in plasma and milk gradually decreased with increasing postpartum time. Their contents were the highest at 0 h postpartum, rapidly decreased after 24 h postpartum, and declined to the lowest on day 14 postpartum. The interaction between dietary energy level and postpartum time showed that although the concentrations of the minerals Ca, P, K, Mg, Fe, Cu, Mn, Zn, Co, Se, and Mo decreased in jennies' plasma and milk in the treatment groups with different energy levels as postpartum time increased, the pattern of change was also influenced by dietary energy level. The influence of dietary energy level in late gestation on the mineral content of milk and plasma during the postpartum colostrum phase was higher than that during the milk phase. In conclusion, this study demonstrated that, under the current experimental conditions, the mineral content of the colostrum, milk, and plasma of jennies after parturition was dependent on the dietary energy level during late gestation.

Feeding the modern sow to sustain high productivity

Selection for hyper-prolific sows has increased the litter size by more than 50% during the last three decades, and proper nutrition of the female pigs has concomitantly changed due to improved prolificacy and productivity of gilts and sows. This review summarizes the physiological characteristics and nutritional challenges associated with feeding modern hyper-prolific sows during the gilt rearing period and during gestation, transition, and lactation periods. The review presents up-to-date knowledge of the energy and lysine requirements of female pigs and focuses on how nutrition may increase fat gain and limit protein and weight gain in the gilt rearing period and in early and mid-gestation. In late gestation, fetal and mammary growth should be considered and during the transition, colostrum yield and farrowing performance need to be optimized. Finally, milk production should be optimized and body mobilization should be minimized in the lactation period to achieve high feed efficiency in hyper-prolific sows.

Placental Malfunction, Fetal Survival and Development Caused by Sow Metabolic Disorder: The Impact of Maternal Oxidative Stress

The energy and metabolic state of sows will alter considerably over different phases of gestation. Maternal metabolism increases dramatically, particularly in late pregnancy. This is accompanied by the development of an increase in oxidative stress, which has a considerable negative effect on the maternal and the placenta. As the only link between the maternal and the fetus, the placenta is critical for the maternal to deliver nutrients to the fetus and for the fetus' survival and development. This review aimed to clarify the changes in energy and metabolism in sows during different pregnancy periods, as well as the impact of maternal oxidative stress on the placenta, which affects the fetus' survival and development.

Dietary supplementation with lysine (protein) in late pregnancy does not enhance mammary development in multiparous sows

This project was conducted to determine if providing standardized ileal digestible (SID) Lys at 40% above estimated requirements (NRC, 2012), with the concomitant increased protein intake, from days 90 to 110 of gestation stimulates mammary development in multiparous sows. From day 90 of gestation, Yorkshire × Landrace multiparous sows (parities 2 and 3) were fed 2.6 kg/d of either a conventional diet (CTL, control, n = 17) providing 14.8 g/d of SID Lys or a diet providing 20.8 g/d of SID Lys via additional soybean meal (HILYS, n = 16). The diets were isoenergetic. Concentrations of IGF-1, glucose, free fatty acids (FFA), urea, and amino acids (AA) were measured in jugular blood samples obtained on days 90 and 110 of gestation. Sows were necropsied on day 110 ± 1 of gestation to obtain mammary glands for compositional and histological analyses. Backfat or BW changes of sows during late gestation were unaffected by treatment (P > 0.10), as was the case for fetal BW (P > 0.10). None of the variables measured in mammary tissue were altered by supplementary Lys (P > 0.10). Circulating IGF-1, glucose, and FFA did not differ (P > 0.10) between HILYS and CTL sows on day 110 of gestation, whereas concentrations of urea were greater (P < 0.01) in HILYS versus CTL gilts. Concentrations of Ile and Thr in plasma were also greater (P < 0.05), and those of Glu were lower (P < 0.01) in HILYS than CTL sows. These results demonstrate that feeding Lys (via protein) above current NRC recommendations during late gestation does not improve mammary development of multiparous sows. Hence, the use of a two-phase feeding strategy to provide more Lys (protein) to multiparous sows during this period is not necessary.

Dietary supplementation with lysine (protein) stimulates mammary development in late pregnant gilts

The goal of this project was to determine if standardized ileal digestible (SID) lysine provided at 40% above estimated requirements, with the concomitant increase in protein intake, from days 90 to 110 of gestation would stimulate mammary development in gilts. From day 90 of gestation, Yorkshire × Landrace gilts were fed 2.65 kg of either a conventional diet (CTL, control, n = 19) providing 18.6 g/d of SID Lys or a diet providing 26.0 g/d of SID Lys via additional soybean meal (HILYS, n = 19). Both diets were isoenergetic. Jugular blood samples obtained on days 90 and 110 of gestation were used to measure concentrations of insulin-like growth factor-1 (IGF-1), metabolites, and amino acids (AA). Gilts were necropsied on day 110 ± 1 of gestation to obtain mammary glands for compositional analyses, immunohistochemistry, and analysis of mRNA abundance for AA transporters and markers of cell proliferation and differentiation. The HILYS gilts gained more body weight (P < 0.01) during the experimental period compared with CTL gilts, and had greater fetal weights (1.29 vs. 1.21 ± 0.03 kg, P < 0.05). There was no difference in circulating IGF-1, glucose, or albumin (P > 0.10) between HILYS and CTL gilts on day 110 of gestation, whereas concentrations of urea and free fatty acids were greater (P < 0.01), and those of Trp and Ala were lower (P < 0.05), in HILYS than CTL gilts. The provision of lysine at 40% above estimated requirements increased total mammary parenchymal mass by 44%, as well as total parenchymal fat, protein, DNA, and RNA (P < 0.01). The mRNA abundance of ACACA was greater (P < 0.05) in HILYS than CTL gilts, while only the AA transporter SLC6A14 tended (P < 0.10) to be greater. Results demonstrate that providing dietary Lys above current National Research Council recommendations in late gestation increases mammary development in gilts. Results also indicate that Lys may have been limiting for protein retention. These data suggest that the use of a two-phase feeding strategy during gestation, whereby dietary Lys is increased from day 90, could benefit potential sow milk yield in the subsequent lactation.

Effects of Energy and Dietary Fiber on the Breast Development in Gilt

To study the effects of energy and dietary fiber on breast development in gilts and its possible mechanisms, 32 gilts (Landrace × Yorkshire) were randomly allocated into a 2 × 2 factorial design to receive a diet with low or high energy [LE: 33.37 MJ/d digestible energy (DE); HE: 41.87 MJ/d DE] and low or high fiber (LF: 0.3 kg/d dietary fiber, HF: 0.6 kg/d dietary fiber). The weight of breast tissue was recorded. The mammary glands were collected for further analyses. The high energy intake increased the relative weight of breast tissue (p < 0.05) and the content of breast fat (p < 0.05). At the same time, the oil red staining of breast slices also showed an increase in breast fat content in high-energy treatment. High energy intake increased the DNA concentration in breast tissues (p < 0.05). In addition, high energy intake increased the concentration of triglycerides, free fatty acids, and total cholesterol in the blood of gilts (p < 0.05), and the supplementation of high fiber tended to reduce free fatty acids, total cholesterol, and estradiol (p < 0.1). Proteomic analysis suggested that there were notable differences in the cytoskeleton, intracellular non–membrane-bounded organelle, apoptosis, receptor activity, and endopeptidase inhibitor activity in molecular function between the energy and fiber effects (p < 0.05). High fiber intake also decreased the mRNA expression of 5-HT7, Bax, and caspase-3 in the breast tissue of gilts (p < 0.05), which further confirmed the importance of fiber in regulating breast development in gilt. Our results indicate that increasing gilt energy intake improved breast weight and fat deposition and increased breast cell apoptosis. Increased fiber intake reduced breast fat deposition and breast cell apoptosis at high energy intake in gilts. These results provide a potential strategy for dietary intervention against high energy intake in gilts and even in humans.

Effects of increasing standardized ileal digestible lysine during gestation on reproductive performance of gilts and sows

Limited information is available on lysine requirement estimates of modern, high-producing gestating sows Therefore, the objective of this study was to evaluate the effects of increasing standardized ileal digestible (SID) lysine during gestation on piglet birthweight and reproductive performance of gilts and sows. A total of 936 females (498 gilts, 438 sows; Camborough®, PIC, Hendersonville, TN) were group-housed (approximately 275 females per pen) and individually fed with electronic sow feeders. Females were moved from the breeding stall to pens on d 4 of gestation and allotted to one of four dietary treatments on d 5. Dietary treatments included increasing SID lysine intake (11.0, 13.5, 16.0, and 18.5 g/d). Gilts (parity 1) and sows (parity 2+) received 2.1 and 2.3 kg (22.2 and 24.3 MJ net energy per day) of feed throughout the entire gestation period, respectively. Dietary treatments were achieved by different blends of low (0.48% SID lysine) and high (0.88% SID lysine) lysine diets, prepared by changing the amount of corn and soybean meal in these two diets. Female weight and backfat were recorded on d 4 and 111 of gestation. Individual piglet weight was obtained within 12 h of birth on litters from 895 females. Final weight, and calculated maternal BW, body lipid, and body lean at d 111 of gestation increased (linear, P < 0.01) for gilts and sows as SID lysine increased. There was no evidence for differences in final backfat depth. Average total born for gilts and sows was 15.3 and 16.0 pigs with no evidence for differences among treatments. The percentage of pigs born alive increased (P = 0.01) with increasing SID lysine intake for sows, but not in gilts as a result of a treatment by parity group interaction (P = 0.04) for percentage of stillborn pigs. Increasing SID lysine intake during gestation did not affect the percentage of mummified fetuses, total born, or birthweight of piglets born alive in this study. In addition, increasing SID lysine intake during gestation did not affect subsequent reproductive performance. In conclusion, increasing dietary SID lysine intake in gestation increased female BW, without changing backfat depth. The minimal effects on female reproductive performance and piglet birthweight suggest that 11 g/day of SID lysine intake appears to be adequate for gestating gilts and sows; however, providing sows with 18.5 g/d SID lysine reduced (P = 0.01) stillbirth rate by 2.3 percentage points.

The role of lactose in weanling pig nutrition: a literature and meta-analysis review

Lactose plays a crucial role in the growth performance of pigs at weaning because it is a palatable and easily digestible energy source that eases the transition from milk to solid feed. However, the digestibility of lactose declines after weaning due to a reduction in endogenous lactase activity in piglets. As a result, some lactose may be fermented in the gastrointestinal tract of pigs. Fermentation of lactose by intestinal microbiota yields lactic acid and volatile fatty acids, which may positively regulate the intestinal environment and microbiome, resulting in improved gastrointestinal health of weanling pigs. We hypothesize that the prebiotic effect of lactose may play a larger role in weanling pig nutrition as the global feed industry strives to reduce antibiotic usage and pharmacological levels of zinc oxide and supra-nutritional levels of copper. Evidence presented in this review indicates that high dietary lactose improves growth performance of piglets, as well as the growth of beneficial bacteria, particularly Lactobacillus, with the positive effects being more pronounced in the first 2 weeks after weaning. However, the risk of post-weaning diarrhea may increase as pigs get older due to reduced lactase activity, high dietary lactose concentrations, and larger feed intakes, all of which may lead to excessive lactose fermentation in the intestine of the pig. Therefore, dietary lactose levels exert different effects on growth performance and gastrointestinal physiological functions in different feeding phases of weanling pigs. However, no formal recommendation of lactose for weanling pigs has been reported. A meta-analysis approach was used to determine that diets fed to swine should include 20%, 15%, and 0 lactose from d 0–7, d 7–14, and d 14–35 post-weaning, respectively. However, sustainable swine production demands that economics must also be taken into account as lactose and lactose containing ingredients are expensive. Therefore, alternatives to lactose, so called “lactose equivalents” have also been studied in an effort to decrease feed cost while maintaining piglet performance with lower dietary lactose inclusions. In summary, the present review investigated dose-response effects of dietary lactose supplementation to exert positive responses and begin to elucidate its mechanisms of action in post-weaning pig diets. The results may help to replace some or all lactose in the diet of weanling pigs, while improving production economics given the high cost of lactose and availability in some swine production markets.

Effects of dietary energy and lysine levels on physiological responses, reproductive performance, blood profiles, and milk composition in primiparous sows

The adequate intake of energy and lysine for primiparous sows are necessary for maternal growth of sows and growth of their progeny. This study was conducted to evaluate the effects of dietary energy and lysine levels on primiparous sows and their progeny. A total of 48 gilts (Yorkshire × Landrace), with an initial body weight (BW) of 168.1 ± 9.71 kg and at day 35 of gestation, were allotted to eight treatment groups with a 2 × 4 factorial arrangement. The first factor was metabolizable energy levels in diet (3,265 or 3,365 kcal of ME/kg), and the second factor was lysine levels in diet (gestation 0.55%, 0.65%, 0.75%, 0.85%, lactation 0.70%, 0.85%, 1.00%, 1.15%). The BW gain (p = 0.07) and backfat thickness (p = 0.09) in the gestation period showed a tendency to be increased in sows fed the high-energy diets. In the lactation period, sows fed the high-energy diets tended to be greater BW (p = 0.09) and less BW loss (p = 0.05) than those of sows fed the low-energy diets. Sows fed high-energy diets had a tendency of greater piglet weight at day 21 of lactation and greater piglet weight gain (p = 0.08 and p = 0.08, respectively). Although the blood urea nitrogen (BUN) was increased linearly as dietary lysine level increased at day 110 of gestation (Linear, p = 0.03), the BUN was decreased linearly as dietary lysine level increase at day 21 of lactation (Linear, p < 0.01). In the composition of colostrum, sows fed high-energy diets had greater casein, protein, total solid, solid not fat, and free fatty acid concentrations than those of sows fed low-energy diets (p < 0.05). Supplementation of total lysine 0.75% for gestation and 1.00% for lactation with 3,365 kcal of ME/kg energy level could be applied to the primiparous sows’ diet to improve performance of sows and growth of their progeny.

Effect of Increasing Dietary Aminoacid Concentration in Late Gestation on Body Condition and Reproductive Performance of Hyperprolific Sows

Simple Summary

Nutrition during gestation is relevant for the success of reproductive sows and the late pregnancy is an especially critical period. Currently, the usual feeding management includes only one diet supplied at different levels through pregnancy and it could not be enough. Additionally, modern sows are producing large litters; their requirements are probably higher than those of commercial sows and they have to be met. With the current study, it can be concluded that a high level of amino acids in the diet provided approximately during the last month of gestation (around 10 g of standardized ileal digestibility lysine/kg of feed, with the remaining essential AA following the ideal protein concept) could be a strategy to improve the sow body condition and the reproductive performances.

Abstract

A total of 62 highly prolific Danbred sows was used to evaluate the implications of increasing dietary amino acid (AA) concentration during late gestation (from day 77 to 107 of pregnancy) on body condition and reproductive performances. Sows were assigned to one of the two treatments (n = 31, with similar number of sows in the second-, third- and fourth-cycle); control diet (containing 6 g of standardized ileal digestible lysine -SID Lys-)/kg) and high AA level (containing 10 g SID Lys/kg and following the ideal protein concept for the remaining essential AA). On day 108 of pregnancy, animals were moved to the farrowing-lactating facilities where they spent until weaning receiving a common standard lactation diet. After farrowing, litters were standardized to 13 piglets each. At 107 d of gestation, backfat depth was thicker in sows fed high AA concentration than in those fed control diet (p < 0.0001) but these significant differences disappeared at weaning (p > 0.05). Additionally, at farrowing, the litter size (p = 0.043) and weight (p = 0.017) were higher in sows fed high AA level. It can be concluded that the increase in the AA content in the feed during the last month of gestation could improve the body condition of the sows and their performance results.

Efficacy of two adjuvant systems to promote humoral immunity to the pre-proghrelin peptide obestatin in pigs: consequences for the growth of piglets to weaning

The poor antigenicity of peptide antigens demands the selection of effective adjuvants to induce humoral immunity. The peptides obestatin and ghrelin from the pro-hormone pre-proghrelin were initially identified as antagonistic in regulating feeding behaviour, with obestatin being suppressive. The efficacy of two adjuvant systems, DEAE with the oil polysorbate emulsion of BP85:Span80 and the surfactant-oil system Montanide (ISA 50v) were therefore assessed with an obestatin-ovalbumin conjugate injected into late pregnant sows. This enabled the supply of antibodies directed against obestatin to newborn piglets through colostrum with the objective of promoting ghrelin secretion and therefore increasing feeding behaviour. Pregnant Landrace × Large White sows (n = 28) were immunised with 0.5 mg obestatin-ovalbumin in 2 mL DEAE:BP85:Span80 (DEAE; n = 14) or with 2 mL Montanide (ISA 50v: n = 14) as adjuvants at days 91 and 105 of gestation. After farrowing, piglets remained with their mothers during the lactation period and were weighed after weaning at Day 28. Antibody titres (unitless) in colostrum were assessed by ELISA as 5543 ± 2388 and 3139 ± 1151 for the DEAE and Montanide adjuvants respectively. These were associated with total IgG of 67.7 ± 3 and 82.3 ± 4.8 mg/mL respectively (P = 0.018). Piglet plasma titres were 5100 ± 1576 and 5762 ± 1688 for DEAE and Montanide respectively at Day 5 postpartum. These titres were still detectable through to Day 28 (titres of 1213 ± 389 and 665 ± 203 respectively (P = 0.176). However, sow colostral antibody titres were not related to piglet antibody concentrations on D5 (r = –0.225, P = 0.341). Sow plasma antibody titres were not related to titres at Day 28 in piglets across treatments (r = 0.198, P = 0.402). The concentration of ghrelin in colostrum was 672 ± 78 and 666 ± 39 pg/mL for the DEAE and Montanide groups, respectively, leading to piglet plasma concentrations on Day 5 of 1105 ± 164 and 530 ± 84 pg/mL (P = 0.002). Animals grew from birthweights of 1.7 ± 0.1 and 1.8 ± 0.1 (P = 0.993) to 7.7 ± 1.2 and 7.8 ± 1.0 kg (P = 0.295) at weaning, representing growth rates of 200.5 ± 52.9 and 225.5 ± 53.4 g/day (P = 0.181). There was a significant negative correlation between piglet D28 antibody titre and growth rate to weaning with the Montanide adjuvant (r = 0.116, P = 0.035) but not for the DEAE (r = –0.118, P = 0.411). Although both adjuvants were capable of generating high antibody titres, the DEAE dextran was likely to be the most effective adjuvant to induce a humoral immune response to develop further with a commercial vaccine.

Tryptophan Supplementation Increases Reproduction Performance, Milk Yield, and Milk Composition in Lactating Sows and Growth Performance of Their Piglets

Tryptophan (Trp) can produce bioactive compounds for appetite regulation, calcium mobilization, and mammary gland homeostasis via a serotonin pathway. This study evaluated the effects of Trp supplementation on the reproduction performance, milk yield, and composition of lactating sows, growth performance of their piglets, and the secretion function of porcine mammary epithelial cells (PMECs). The infrared emulsion analyzer and ELISA analyses revealed that feeding sows with a 0.12% Trp addition increased ( P < 0.05) sow average daily feed intake, milk yield, milk calcium concentration, average daily gain of piglets, fatty acid synthase (FAS) and lactose synthase (LS), β-casein secretion, intracellular Ca²⁺ level, the expression of calcium binding protein CaM, and the activity of CaMKII. In a cellular experiment of PMECs treated with Trp, ELISA and flow cytometry analyses revealed that the pretreatment of a Trp hydroxylase inhibitor reduced ( P < 0.05) FAS and LS synthesis, the intracellular Ca²⁺ level, and the activity of CaMKII. In conclusion, Trp supplementation at 0.12% increased sows' reproductive performance, milk yield, and calcium concentration and piglets' growth performance. Milk yield increased by Trp was linked to 5-hydroxytryptamine-mediated synthesis of FAS, LS, and β-casein in PMECs, while the increase in calcium concentration was attributed to increasing CaM expression and CAMKII activity.

Effects of dietary energy levels on physiological parameters and reproductive performance of gestating sows over three consecutive parities

OBJECTIVE

This experiment was to evaluate the effects of the dietary energy levels on the physiological parameters and reproductive performance during gestation over three parities in sows.

METHODS

A total of 52 F1 gilts (Yorkshire×Landrace) were allotted to one of four dietary treatments using a completely randomized design. The treatments contained 3,100, 3,200, 3,300, or 3,400 kcal of metabolizable energy (ME)/kg diet but feed was provided at 2.0, 2.2, and 2.4 kg/d in the first, second and third parity, respectively.

RESULTS

The body weight and body weight gain during gestation increased as the dietary energy level increased (p<0.05, and p<0.01) in the first parity. In the second parity, the body weight of sows was the lowest (p<0.05) when 3,100 kcal of ME/kg treatment diet was provided. The body weight was higher as the dietary energy level increased (p<0.05) during the gestation period in the third parity. During lactation, the voluntary feed intake of lactating sows tended to decrease when gilts were fed higher energy treatment diet (p = 0.08) and the body weight, body weight gain were increased by dietary energy level during gestation (p< 0.05). Backfat thickness was not affected by dietary treatment during the gestation period in three parities, interestingly backfat change from breeding to d 110 of gestation was higher as the dietary energy level increased at the first parity (p<0.05). When gilts were fed 3,400 kcal of ME/kg treatment diet a higher number of weaning piglets was observed in the first parity (p<0.05). The highest culling rate (69%) was seen when gestating sows were fed 3,100 kcal/kg ME treatment diet during three parities.

CONCLUSION

In conclusion, the adequate energy intake of gestating sows should be 6,400 or 6,600 kcal of ME/d, 7,040 or 7,260 kcal of ME/d, and 7,680 or 7,920 kcal of ME/d for parity 1, 2, and 3, respectively.

Elevating glucose and insulin secretion by carbohydrate formulation diets in late lactation to improve post-weaning fertility in primiparous sows

Primiparous (P1) sows commonly lose excessive body reserves to meet energy requirements for maintenance and milk production during lactation, and consequently, post-weaning reproductive performance may be compromised. The present studies determined whether ad libitum feeding a glucogenic carbohydrate diet (CHO) during late lactation could stimulate insulin and glucose secretion (experiment 1) and improve subsequent litter size (experiment 2). For experiment 1, 15 P1 sows, and for experiment 2, 99 P1 sows (198.5 ± 2.7 kg) were allocated randomly according to suckled litter size (≥10 piglets), either to a CHO diet (14.3 MJ DE/kg, 19.8% crude protein) or a standard lactation diet (control; 14.2 DE MJ/kg, 19.5% crude protein) at 8 days before weaning. The CHO diet aimed to provide glucogenic content (extruded wheat, dextrose and sugar) as energy sources instead of fat sources without changing total dietary energy. Pre-prandial plasma glucose and insulin concentrations were not influenced by treatments. However, post-prandial plasma glucose and insulin concentrations and their peaks were both higher (p < .05) compared to the control treatment. Body weight loss during lactation was relatively low at 3%-4% for both treatments and did not differ between control and CHO treatments (-7.6 ± 1.6 vs -5.4 ± 1.2 kg; p > .05). Second litter size was not influenced by diet (p > .05), but the weaning-to-mating interval was shorter in CHO sows (p < .05). This study demonstrates that providing an enriched CHO diet in late lactation did influence post-weaning follicle growth but did not improve subsequent litter size. This may be due to the primiparous sows in this study not experiencing severe negative energy balance and there was no second litter syndrome in this farm which limited the ability of diet to improve sow fertility.

Effects of Dietary Energy Levels on the Physiological Parameters and Reproductive Performance of Gestating Gilts

This experiment was conducted to investigate the effects of dietary energy levels on the physiological parameters and reproductive performance of gestating first parity sows. A total of 52 F1 gilts (Yorkshire×Landrace) were allocated to 4 dietary treatments using a completely randomized design. Each treatment contained diets with 3,100, 3,200, 3,300, or 3,400 kcal of metabolizable energy (ME)/kg, and the daily energy intake of the gestating gilts in each treatment were 6,200, 6,400, 6,600, and 6,800 kcal of ME, respectively. During gestation, the body weight (p = 0.04) and weight gain (p = 0.01) of gilts linearly increased with increasing dietary energy levels. Backfat thickness was not affected at d110 of gestation by dietary treatments, but increased linearly (p = 0.05) from breeding to d 110 of gestation. There were no significant differences on the litter size or litter birth weight. During lactation, the voluntary feed intake of sows tended to decrease when the dietary energy levels increased (p = 0.08). No difference was observed in backfat thickness of the sows within treatments; increasing energy levels linearly decreased the body weight of sows (p<0.05) at d 21 of lactation and body weight gain during lactation (p<0.01). No significant differences were observed in the chemical compositions of colostrum and milk. Therefore, these results indicated that high-energy diets influenced the bodyweight and backfat thickness of sows during gestation and lactation. NRC (2012) suggested that the energy requirement of the gestation gilt should be between 6,678 and 7,932 kcal of ME/d. Similarly, our results suggested that 3,100 kcal of ME/kg is not enough to maintain the reproductive performance for gilts during gestation with 2 kg feed daily. Gilts in the treatment 3,400 kcal of ME/kg have a higher weaning number of piglets, but bodyweight and backfat loss were higher than other treatments during lactation. But bodyweight and backfat loss were higher than other treatments during lactation. Consequently, an adequate energy requirement of gestating gilts is 6,400 kcal of ME/d.

Undernutrition during early follicle development has irreversible effects on ovulation rate and embryos

This study assessed carry-over effects of energy level during the early antral phase and subsequent follicular phase on follicle recruitment and ovulation rate. Gilts (n=45) were fed a standard diet to a low (L, ~1.2kg day(-1)) or high (H, ~2.7kg day(-1)) level during the early antral (luteal) phase, and subsequently fed a H or L feed level during the follicular phase, resulting in four treatment groups (HH, HL, LH and LL). Follicle size at the end of the luteal phase was greater for gilts fed a high feed level previously (3.3vs3.0mm; P<0.05). During the follicular phase, high feeding increased follicle size at Day 5 (6.9vs6.2mm; P<0.005) and plasma oestradiol concentration (P<0.05). Nevertheless, a low feed level during the luteal phase reduced ovulation rate (14.4vs13.2; P<0.05) and embryo number (12.6vs10.5; P<0.05), and this was not counteracted by feed level during the follicular phase. Plasma progesterone concentration after ovulation was lower for LL gilts than for other treatments (P<0.05). These results indicate that undernutrition during early antral follicle development may have a residual effect on follicle recruitment and quality.

The effect of the ratio of standardized ileal digestible lysine to metabolizable energy on growth performance, blood metabolites and hormones of lactating sows

A total of 335 lactating sows (Landrace × Large White) were used in two experiments to determine the optimum ratio of standardized ileal digestible lysine (SID-Lys) to metabolizable energy (ME) for mixed parity sows during lactation. In Exp. 1, 185 sows (weighing an average of 256.2 ± 6.5 kg and having an average parity of 3.4 ± 0.3) were allocated to one of six experimental diets in a completely randomized block design within parity groups (1, 2, and 3+). The experimental diets were formulated to contain 3.06, 3.16, 3.20, 3.25, 3.30 or 3.40 Mcal/kg of ME and each diet was fed to the sows throughout a 28 day lactation. All diets provided a similar SID-lysine level (0.86%). As a result, the diets provided a SID-Lys:ME ratio of 2.81, 2.72, 2.69, 2.65, 2.61 or 2.53 g/Mcal ME. Sow feed intake was significantly (P < 0.01) affected by the energy content of the diet as well as by sow parity. Using regression analysis, feed intake was shown to be maximized at 3.25, 3.21, 3.21 and 3.21 Mcal/kg of ME for parity 1, 2, 3+ sows and the entire cohort of sows respectively (quadratic; P < 0.01). In addition, the result of feed intake can be expressed as 2.65, 2.69, 2.69 and 2.68 g/Mcal based on analysis of SID-Lys:ME ratio. Litter weight gain was affected by dietary treatment for parity 3+ sows and the entire cohort (P < 0.01). Based on regression analysis, litter weight gain was maximized at 3.25 and 3.24 Mcal/kg of ME for parity 3+ (quadratic; P < 0.01) and the entire cohort (quadratic; P < 0.01). Similarly, the result of litter weight gain could be expressed as 2.65 and 2.66 g/Mcal of SID-Lys:ME ratio. Therefore, 3.25 Mcal/kg of ME was selected for Exp. 2 in which 150 sows (weighing 254.6 ± 7.3 kg and having an average parity of 3.4 ± 0.4) were allocated to one of five treatments in a completely randomized block design within parity (1, 2, and 3+). The experimental diets were formulated to contain 2.1, 2.4, 2.7, 3.0 or 3.3 g/Mcal of SID-Lys:ME ratio with all diets providing 3.25 Mcal/kg of ME. The diets were fed to the sows throughout a 28 day lactation. Sow body weight loss was affected by dietary treatment (parity 3+ sows, P = 0.02; entire cohort, P < 0.01) and by sow parity (P < 0.01). Litter weight at weaning and litter weight gain were affected by dietary treatment for parity 1, 2, 3+ sows and the entire cohort (P < 0.01) as well as by sow parity (P < 0.01). Plasma urea nitrogen (P < 0.01), creatinine (P < 0.01) and non-esterifide fatty acids (P = 0.04) were decreased as the SID-Lys:ME ratio of the diet increased. Insulin-like growth factor-1 (P = 0.02), estradiol (P < 0.01) and luteinizing hormone (P = 0.02) were increased as the SID-Lys:ME ratio in diet increased. Based on a broken-line model, the estimated SID-Lys:ME ratio to maximize litter weight gain was estimated to be 3.05 g/Mcal.

Post-farrowing stress management in sows by administration of azaperone: effects on piglets performance

This study examined the impact of a single dose of azaperone administered to sows at the end of farrowing on piglet weight gain and mortality during the lactation period. Two hundred fifty-two sows (JSR hybrid) housed in a conventional farrowing crate system were assigned to either a treatment or a control group. The parities of the sow were between 1 and 6. The differences between live birth weight and weight at weaning were recorded for 3,093 individual piglets. Serum concentrations of IgG of 485 piglets also were recorded during tail docking. Median and interquartile range (IQR) were 5.1 (2.9 to 9.5) mg·mL(-1) in the control group and 5.6 (3.1 to 12.1) mg·mL(-1) in the azaperone group (P > 0.05). Litter size was 13.0 (11 to 15) total born piglets and birth weight was 1.28 (1.05 to 1.52) kg. Weaning weight for the control group was 5.64 (4.73 to 6.54) kg compared with 5.78 (4.79 to 6.71) kg for the azaperone treated group (P = 0.005). Daily BW gain differed significantly (P = 0.001) between the 2 groups, 205 g for the controls, compared with 214 g for the azaperone group. There were no significant differences between piglet mortality rates (17% and 20%). Azaperone applications to sows tended to have a positive effect on productivity. Effect was greatest in the primiparous sows and declined with increasing parity. This may have been due to both physiological and behavioral differences between the sows as they experienced increasing numbers of gestations, farrowings, and lactation periods.

The effect of feeding a high fibre diet on the welfare of sows housed in large dynamic groups

This study assessed the effect of increasing fibre levels in the concentrate ration on the welfare of sows housed in a large dynamic group. One hundred and twelve Large White * Landrace sows were allocated to one of two treatments over six replicates. Treatments were as follows: (i) High Fibre diet (~15% CF [Crude Fibre]), and (ii) Control diet (~5% CF). Treatments were applied to two separate dynamic groups each containing 33 (±3) sows in a cross-over design, after three replicates the treatments were switched between the groups. Approximately nine sows were replaced in each of these groups at 3-week intervals (each replacement constituting a replicate of the study). Sows on the high fibre diet spent a greater percentage of time lying (High Fibre: 43.8, Control: 28.0, SEM 3.25%), while sows on the control diet spent more time sham chewing (High Fibre: 7.2, Control: 28.8, SEM 1.55%). Sows newly introduced to the group on the high fibre treatment spent proportionally more time in the kennel areas compared to newly introduced sows in the control treatment (High Fibre: 0.893, Control: 0.788, SEM 5.10). In general, aggression occurred at a very low frequency and overall levels did not differ between treatments (High Fibre: 0.005, Control: 0.003, SEM 0.0007 [occurrences per min]). However, sows in the control treatment performed head thrusting (High Fibre: 0.02, Control: 0.00, SEM 0.001 [occurrences per min]), and biting behaviour (High Fibre: 0.02, Control: 0.01, SEM 0.002 [occurrences per min]) more frequently than sows on the high fibre diet. There was no effect of treatment on physiological parameters such as plasma cortisol (High Fibre: 1.34, Control: 1.44, SEM 0.114 ng ml−1) or haptoglobin levels (High Fibre: 0.73, Control: 0.64, SEM 0.080 mg ml−1). In summary, provision of a high fibre diet had a positive effect on the welfare of group-housed dry sows. Sows on the high fibre treatment spent more time resting in the kennel areas, less time performing stereotypic behaviours and showed a reduction in some aggressive behaviours relative to sows fed the control diet.

Nutritional, hormonal, and environmental effects on colostrum in sows

It is widely recognized that an early and high intake of colostrum is a major determinant of piglet survival during the early suckling period. The production of colostrum, however, is very variable among sows and the factors affecting this variability are not well known. Factors such as number of parity and genotype do seem to influence colostrum yield and composition. The endocrine status of the sow also affects the process of colostrogenesis and changes in the sow endocrine status can have an impact on quantity and quality of colostrum produced. Indeed, induction of parturition seems to play a role. Nutrition is undoubtedly a major factor that could be used as a tool to alter colostrum composition, with fat content being the most affected. Feed ingredients, such as yeast extracts and fermented liquid feed, were recently shown to alter colostrum composition, yet more research is needed to substantiate these effects. Very few data are available on the influence of environment on colostrum production; results suggest that heat stress has negative effects on colostrum composition. Considering the importance of colostrum for the survival, growth, and immune resistance of piglets, it is obvious that research on the development of new management systems is necessary to improve yield and composition of colostrum.