Supplementation of palmitoleic acid improved piglet growth and reduced body temperature drop upon cold exposure.

Piglet survival is a major challenge in the first few days postpartum and interventions during this period may improve survival and growth. This study investigated the effects of palmitoleic acid (C16:1n-7; PA) supplementation on growth performance, body temperature, fatty acid (FA), and energy metabolism in milk-replacer-fed piglets. Forty-eight piglets were stratified by body weight and randomly assigned to one of four dietary treatments (0%, 1%, 2%, and 3% PA supplementation as a percent of milk replacer) and given the diet through an orogastric tube. They were fed dietary treatments every 2 h for 4 d in the first week postpartum and all were sacrificed at the end of the experiment. The piglets were weighed daily, and half in each dietary treatment group, the same piglets each day, were exposed daily to a lower temperature for 2 h. Plasma samples were collected immediately before sacrifice for analyses of FA and other plasma metabolites. The weight of organs and empty body weight were determined after sacrifice. Liver and semimembranosus muscle tissue samples were collected and analyzed for FA content. Contents of C16:1n-7 and C18:1n-7 in both plasma and liver (P < 0.001), and C16:1n-7 in semimembranosus muscle (P < 0.001) increased linearly as PA supplementation increased. Most plasma FA levels (except C16:1n-7, C16:1n-9, and C22:5n-3) were lower in piglets exposed to lower temperatures than those that were not. Plasma glucose, triglycerides, and lactate dehydrogenase levels increased linearly with PA supplementation (P < 0.001). Piglets' average daily gain, liver glycogen pool, liver weight, and gallbladder weight increased linearly (P < 0.05, P < 0.01, P < 0.05, and P < 0.001, respectively), but lung weight, liver nitrogen content, and body temperature drop decreased linearly (P < 0.01, P < 0.001, and P < 0.05, respectively) with PA supplementation. Piglets exposed to low temperature had greater liver nitrogen (P < 0.05) and lactate dehydrogenase (P < 0.001) contents but had lower liver weight (P < 0.01) and plasma lactate concentration (P < 0.05) than those that were not. In conclusion, this study demonstrated the importance of PA on the growth performance of the piglets by increasing their average daily gain and decreasing a drop in body temperature upon cold exposure, most likely due to a modified energy metabolism.

Reducing piglet mortality in the early days after birth is a significant challenge in the modern pig industry. The focus on achieving larger litter sizes has had a negative impact on piglets' birth weight and their intake of colostrum. Additionally, piglets are born without easily oxidizable brown adipose tissue and have limited body reserves, making them more vulnerable to death due to their lower capacity for thermogenesis. Therefore, it is important to explore dietary strategies that can enhance piglets' thermogenesis capacity. In this study, the role of palmitoleic acid supplementation was investigated in a dose-response design to determine its impact on growth performance, fatty acid composition, and energy metabolism of milk-replacer-fed piglets during their first week of life. The results revealed a linear increase in the average daily gain of the piglets, liver weight, and liver glycogen content with increasing palmitoleic acid supplementation. Moreover, increased palmitoleic acid supplementation was associated with a drop in body temperature when piglets were exposed to a lower temperature during the experimental period. Altogether, the study indicated that palmitoleic acid has a sparing effect on glycogen reserves and that a greater proportion of energy utilized by the piglets to maintain their body temperature was derived from the oxidation of fatty acids. The results indicated a promising approach to improve piglet survival and growth through dietary modifications of fatty acids in the diet.

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.

Review: Physiology and nutrition of late gestating and transition sows.

The physiology during late gestation and the transition period to lactation changes dramatically in the sow, especially during the latter period. Understanding the physiological processes and how they change dynamically as the sow approaches farrowing, nest building, giving birth to piglets, and producing colostrum is important because these processes greatly affect sow productivity. Glucose originating from assimilated starch accounts for the majority of dietary energy, and around farrowing, various organs and peripheral tissues compete for plasma glucose, which may become depleted. Indeed, physical activity increases shortly prior to farrowing, leading to glucose use by muscles. Approximately ½ to 1 d later, glucose is also needed for uterine contractions to expel the piglets and for the mammary gland to produce lactose and fat for colostrum. At farrowing, the sow appears to prioritize glucose to the mammary gland above the uterus, whereby insufficient dietary energy may compromise the farrowing process. At this time, energy metabolism in the uterus shifts dramatically from relying mainly on the oxidation of glucogenic energy substrates (primarily glucose) to ketogenic energy supplied from triglycerides. The rapid growth of mammary tissue occurs in the last third of gestation, and it accelerates as the sow approaches farrowing. In the last 1 to 2 wk prepartum, some fat may be produced in the mammary glands and stored to be secreted in either colostrum or transient milk. During the first 6 h after the onset of farrowing, the uptake of glucose and lactate by the mammary glands roughly doubles. Lactate is supplying approximately 15% of the glucogenic carbon taken up by the mammary glands and originates from the strong uterine contractions. Thereafter, the mammary uptake of glucose and lactate declines, which suggests that the amount of colostrum secreted starts to decrease at that time. Optimal nutrition of sows during late gestation and the transition period should focus on mammary development, farrowing performance, and colostrum production. The birth weight of piglets seems to be only slightly responsive to maternal nutrition in gilts; on the other hand, sows will counterbalance insufficient feed or nutrient intake by increasing mobilization of their body reserves. Ensuring sufficient energy to sows around farrowing is crucial and may be achieved via adequate feed supply, at least three daily meals, high dietary fiber content, and extra supplementation of energy.

The transition period is a short period of the reproductive cycle spanning from 7­10 d prepartum to 3­5 d postpartum in sows. Nonetheless, it is highly important for the productivity of sows because it is when the majority of piglet deaths occur. Most piglets die either during the birth process or within the first days postpartum, and mammary development, fetal growth, farrowing process, and colostrum production have profound impacts on piglet survival and growth. Nutrition during this critical period can greatly affect these physiological processes, and the most effective feeding strategy needs to be elaborated. Around farrowing, the sow may suffer from inadequate energy from assimilated starch, and liver glycogen seems not to be able to supply sufficient glucose to meet the demand for nest building, uterine contractions, and colostrum production. The sow seems to prioritize glucose for the mammary gland above the uterus but may suffer from depletion due to nest building. The insufficient energy status of the sow compromises the farrowing process and prolongs the duration, thereby increasing the need for farrowing assistance and stillbirths. Nutritional strategies to alleviate these challenges include adequate feed supply, number of daily meals, dietary fiber content, and extra supplementation of energy to sows around farrowing.

Impact of four fiber-rich supplements on nutrient digestibility, colostrum production, and farrowing performance in sows.

This study aimed to investigate the impact of dietary fiber (DF) sources on sow and litter performance, and apparent total tract digestibility (ATTD) of gross energy (GE) and nutrients. A total of 48 sows were stratified for body weight at mating and randomly assigned to one of four DF sources (mixed fiber [MF], palm kernel expellers [PKE], sugar beet pulp [SBP], or soy hulls [SH]) and fed the diet from mating until farrowing. Within DF treatments, sows were supplemented with one of two extra energy sources (glycerol or sugar dissolved in water), whereas a third group (control) received water from day 108 of gestation until farrowing. The number of total born, live-born, and stillborn pigs; birth time and birth weight of the pigs; farrowing duration; and farrowing assistance (FA) were recorded. Live-born pigs were weighed again at 12 and 24 h after birth to record weight gain, which was used to estimate intake and yield of colostrum. Blood samples were collected once daily from day -3 relative to farrowing until day 1 after farrowing in sows and once from selected pigs right after birth. Fecal samples were collected on day 114 of gestation and colostrum at 0, 12, 24, and 36 h after onset of farrowing. Intake of soluble and insoluble nonstarch polysaccharides (NSP) was greater for SBP (P < 0.001) and PKE (P < 0.001) supplemented sows, respectively, when compared with other groups. Farrowing duration and stillbirth rate were not affected by DF sources, but PKE and SH supplemented sows had greater FA than SBP and MF supplemented sows (P < 0.001). Extra energy supplement did not improve the farrowing performance. Concentration (P = 0.02) and output (P = 0.04) of dry matter in colostrum, and ATTD of GE (P < 0.001) and crude protein (CP; P < 0.001) were lower for PKE supplemented sows than in sows from the remaining groups. Intake of insoluble NSP correlated negatively with ATTD of GE (P < 0.001) and CP (P < 0.001). Concentrations of glucose (P < 0.001), lactate (P < 0.001), CO2 (P < 0.001), and HCO3 (P < 0.001) in sows blood were increased with time progress relative to farrowing. Newborn pigs from PKE supplemented sows had greater concentration of lactate (P = 0.02) and lower blood pH (P = 0.02) than the remaining treatments. In conclusion, PKE supplement reduced ATTD of GE and CP, and concentration and output of dry matter in colostrum but increased FA. Results of this experiment indicated that the use of PKE as a fiber source for late gestating sows should be avoided.

Intravenous infusion of glucose improved farrowing performance of hyperprolific crossbred sows.

The sow at parturition is challenged with respect to energy status due to increases in energetic expenses associated with 1) nest building 2) uterine contractions, and 3) colostrum production. A previous study indicated that sows were depleted of glucogenic energy around farrowing. The aim was to investigate whether intravenous infusion of glucose from observed nest-building behavior to 24 h postpartum affected the farrowing kinetics and colostrum production in sows. Ten multiparous sows (DanBred landrace × DanBred Yorkshire) were fitted with a jugular vein catheter on each side (one for infusion and the other one for blood sampling). Sows were infused with either 0.9% saline (CON; n = 5) or 10% glucose (GLU; n = 5) solution at a constant rate of 125 mL/h. From day 108 of gestation, sows were fed once daily with 3.33 kg of a standard lactation diet. During farrowing, sows were monitored to register the onset of farrowing, time of birth, birth status (live or dead), sex, stillbirth rate (SR), and weight of newborn piglets. Farrowing assistance (FA) was provided when the birth interval exceeded 60 min. In late gestation, 1 mL of blood was collected every third hour for blood gas analysis and every sixth hour for harvesting plasma. During farrowing, 1 mL (for blood gas) and 9 mL of blood were collected at 0, 3, 6, 9, 12, 15, 18, 21, and 24 h in milk (HIM). Colostrum and milk samples were collected at 0, 6, 12, 18, 24, and 36 HIM and also at 3, 10, 17, and 24 d in milk. Compared with CON sows, GLU infusion decreased the SR (16.1% vs. 7.4%; P = 0.03), FA (21% vs. 9.0%; P = 0.01), and surprisingly also blood glucose at the onset of farrowing (5.53 vs. 5.09 mmol/L; P = 0.03), respectively. A tendency to higher plasma lactate at the onset of farrowing (P = 0.05) but decreased piglet mortality from 0 to 24 h (P = 0.06) was also found for GLU sows. No effects of treatment on farrowing duration or mean birth intervals were found. Lactate in whole blood (P = 0.003) and plasma (P = 0.002) was increased for GLU sows as compared with CON sows during the colostrum period. No effect of GLU infusion was seen on colostrum and milk composition and yield. The increase in lactate was most likely due to a shift toward a greater proportion of glucose oxidation and insufficient O2 supply to fuel uterine contractions. In conclusion, infusion of glucose reduced the frequency of SR and FA, and improved energy status of the sow which seems to be crucial to enhance total piglet survival.

Optimal feed level during the transition period to achieve faster farrowing and high colostrum yield in sows.

This study aimed to determine the optimal supply of lactation feed during the transition period to minimize farrowing duration (FD) and maximize colostrum yield (CY) and quality with the overall aim of reducing piglet mortality. A total of 48 sows were stratified for body weight and assigned to six levels of feed supply (1.8, 2.4, 3.1, 3.7, 4.3, and 5.0 kg/d) from day 108 of gestation until 24 h after the onset of farrowing. The number of total born, live-born, and stillborn piglets; birth time and birth weight of each piglet; and frequency of farrowing assistance (FA) was recorded, and blood samples were obtained from newborn piglets at birth. Live-born piglets were further weighed at 12 and 24 h after birth to record weight gain, which in turn was used to estimate intake and yield of colostrum. Colostrum samples were collected at 0, 12, 24, and 36 h after the onset of farrowing. FD was shortest (4.2 h) at intermediate (3.7 kg/d), longest (7.1 to 7.6 h) at low (1.8 and 2.4 kg/d), and intermediate (5.6 to 5.7 h) at high (4.3 and 5.0 kg/d) feed intake (P = 0.004; mean comparison). FA was lowest (0.7% to 0.8%) at intermediate feed intake (3.7 and 4.3 kg/d) and substantially elevated (4.3% to 4.7%) at both lower and higher feed intake (P = 0.01; mean comparison). The cubic contrast revealed 4.1 kg/d as the optimal feed intake to achieve the shortest FD and to minimize FA. Newborn piglets from second-parity sows were less vital than piglets from gilts as evaluated by blood biochemical variables immediately after birth. CY was greatest at 3.1 kg/d (P = 0.04), whereas the cubic contrast revealed 3.0 kg/d as the optimal feed intake to maximize CY. Concentrations of colostral components were affected by the diet, parity, and their interaction except for lactose concentrations. In conclusion, the study demonstrated the importance of proper feed level during the transition period on sow productivity. Moreover, this study estimated 4.1 and 3.0 kg/d as the optimal feed intake during the transition period to improve farrowing characteristic and CY, respectively, and these two feed intake levels supplied daily 38.8 MJ metabolizable energy (ME) and 23.9 g standardized ileal digestible (SID) lysine (3.0 kg/d) or 53.0 MJ ME and 32.7 g SID lysine (4.1 kg/d). The discrepancy of optimal feed intake for optimal farrowing and colostrum performance suggests that it may be advantageous to lower dietary lysine concentration in the diet fed prepartum.

Mammary metabolism and colostrogenesis in sows during late gestation and the colostral period.

The aims of this study were to investigate 1) the effect of high dietary fiber (DF; 19.3% to 21.7%) supplemented to late gestating sows on mammary uptake and metabolism of energy substrates as well as colostrum production and 2) the ontogeny of colostral fat and lactose synthesis using mammary carbon balance, and colostral protein using IgG as a biomarker. Sows were fed either a control diet (CON) consisting of a standard gestation diet (14.6% DF) until day 108 of gestation and a transition diet (16.8% DF) from day 109 of gestation until farrowing or a high DF treatment where part of the daily ration was replaced with a high DF supplement (FIB). The FIB sows received 19.3% and 21.7% DF in the last 2 wk prior to farrowing. Sows were surgically implanted with permanent indwelling catheters at day 75 ± 2 of gestation and blood samples were collected at 6 different time points in late gestation and at 11 different time points within 24 h after the onset of farrowing. Colostrum samples were collected at 0, 12, and 24 h after the onset of farrowing. Arterial concentration of acetate (P = 0.05) and colostral fat content (P = 0.009) were greater in FIB sows compared with CON sows. Plasma IgG dropped from day -10 relative to farrowing (P < 0.001), suggesting an uptake by the mammary glands. Mammary plasma flow (P = 0.007) and net mammary uptake of glucose (P = 0.04) increased during farrowing while dietary treatment had no effect on net mammary uptake of other energy substrates during late gestation and farrowing. The net mammary uptake of carbon from glucogenic precursors did not equate to the sum of carbons secreted in colostral lactose and released as CO2, indicating that carbons from ketogenic precursors were likely used for colostral fat and for oxidation. Mammary nonprotein carbon uptake matched the mammary output, indicating that the majority of colostral fat and lactose were produced after the onset of farrowing. In conclusion, high DF included in the diet for late gestating sows increased colostral fat content by 49% but this substantial dietary response could not be explained by the increased carbon uptake from short chain fatty acids during the colostral period. The nonprotein carbon balance of mammary glands during farrowing suggests that the majority of colostral fat and lactose were produced after the onset of farrowing, whereas the drop in plasma IgG in late gestation suggests that the mammary glands take up this colostral component prior to farrowing.

Impact of sow energy status during farrowing on farrowing kinetics, frequency of stillborn piglets, and farrowing assistance.

Farrowing duration is rather long in sows most likely due to selection for large litters, and we hypothesized that prolonged farrowings would compromise sow energy status during farrowing and in turn the farrowing process. Two studies were performed as follows: 1) to evaluate whether sow energy status during farrowing compromise the farrowing kinetics (FK, i.e., farrowing duration and birth intervals) and 2) to study the underlying mechanisms potentially affecting stillbirth rate and farrowing assistance. In study-1, parameters affecting FK were characterized based on data from a total of 166 farrowings from 7 feeding trials focused on sow colostrum production. The data were screened for associations with FK using the CORR procedure of SAS. Traits that were correlated with the FK at P < 0.05 were included in a multivariate regression model. Time since last meal until the onset of farrowing greatly affected the farrowing duration (r = 0.76; n = 166; P < 0.001) and a broken-line model was fitted to describe that relationship. According to the model, farrowing duration was constant (3.8 ± 1.5 h) if the farrowing started before the breakpoint (3.13 ± 0.34 h after the last meal), whereas farrowing duration increased to 9.3 h if the farrowing started 8 h after the last meal. Subsequently, sows were divided into 3 categories based on that trait (≤3, 3 to 6, and >6 h) to evaluate the impact on birth intervals, farrowing assistance, and stillbirth rate. Birth intervals (P < 0.001), odds for farrowing assistance (P < 0.001), and odds for stillbirth (P = 0.02) were low, intermediate, and high when time since last meal was ≤3, 3 to 6, and >6 h, respectively. In study-2, blood samples were collected once or twice each week in late gestation and each hour during farrowing to measure arterial concentrations and uterine extractions of plasma metabolites. Time since last meal was strongly negatively correlated with arterial glucose 1 h after the onset of farrowing (r= -0.96; n = 9; P < 0.001). Glucose appeared to be the key energy metabolite for oxidative metabolism of gravid uterus. In conclusion, the present study strongly suggests that a substantial proportion of sows suffer from low-energy status at the onset farrowing and that this negatively affects the farrowing process. Transferring this knowledge into practice, the results suggest that sows should be fed at least 3 daily meals in late gestation.