Effects of dietary carbohydrate sources on plasma glucose, insulin and IGF-I levels in multiparous sows

Effects of different carbohydrate sources on plasma glucose, insulin and insulin-like growth factor-I (IGF-I) levels were compared to subsequently be able to study effects of insulin-stimulating diets on follicle development in sows. The following feed components were tested in 12 sows during six consecutive test periods of 9.5 days: dextrose (DEX), sucrose (SUC), lactose (LAC), dextrose plus lactose (DL), sucrose plus lactose (SL), dextrose plus sugarbeet pulp (DSBP) and control (CON). On day 2, 5 and 9 of each test period, plasma glucose (only at day 9), insulin and IGF-I profiles were determined. Despite similar glucose profiles for all diets, the postprandial insulin response was higher for DL and SL compared with CON and LAC; the other diets were intermediate. Plasma IGF-I levels were higher in CON, LAC and SL compared with DSBP, but differences were only marginal. It was concluded that dextrose and sucrose have the potential to stimulate fast and high insulin peaks, especially when combined with additional lactose. Despite the high dextrose in the DSBP diet, the insulin response was flattened, probably due to the viscosity of sugarbeet pulp. The results show that modulation of plasma insulin levels by dietary carbohydrates seems possible in anabolic sows, but IGF-I levels are less easily modified.     

Effects of feeding zearalenone to sows on rebreeding and pregnancy

Two trials were conducted with a total of 91 lactating sows fed 0, 5 or 10 ppm dietary zearalenone (Z) and 0 or 15% dietary alfalfa in a factorial arrangement to evaluate their influence on reproductive performance to 40 d postbreeding. Feeding of Z did not alter the proportion of sows returning to estrus; however, the weaning-to-estrus interval increased when increased dietary Z was fed in Trial 2, with a similar trend at the highest level in Trial 1. The average number of fetuses per sow with fetuses tended to decrease (P less than .05) with increasing dietary Z in Trial 2, but not in Trial 1. Embryonic mortality did not appear to increase when the ratio of fetuses to corpora lutea was compared in sows with fetuses in Trial 1, but it did increase in Trial 2. The trend to increased numbers of bred sows that were non-pregnant at slaughter when dietary Z increased in Trial 1 was not observed in Trial 2. Dietary dehydrated alfalfa meal did not appear to modify the effects of Z in these trials.     

Effects of season and breed on the feeding behavior of multiparous lactating sows in a tropical humid climate

The effects of breed and season on performance and feeding behavior were studied during 76 lactations in multiparous Large White (LW; n = 17) and Creole (CR; n = 23) sows reared in a humid tropical climate. The experiment was conducted in Guadeloupe (French West Indies, latitude 16 degrees N, longitude 61 degrees W) between May 2002 and July 2004. Average daily ambient temperature was greater during the hot season than during the warm season (26.0 vs. 23.8 degrees C), but relative humidity was similar in both seasons (85% on average). The daily fluctuations of ambient temperature and relative humidity were similar for both seasons. At farrowing, BW was lower (187 vs. 265 kg) and backfat thickness was greater (40 vs. 22 mm) in CR than in LW sows (P < 0.01). Sows were offered feed ad libitum between the fifth and the 26th day of lactation. There was a breed x season interaction (P < 0.05) for ADFI. During the hot season the reduction of ADFI was more pronounced in LW than in CR sows (-1,100 vs. -300 g/d). Irrespective of breed and season, the daily number of meals was 9.0. The meal size and the rate of feed intake were greater in LW than in CR sows, respectively (555 g and 153 g/min vs. 390 g and 83 g/min; P < 0.01). The diurnal proportion of ADFI was greater in CR than in LW sows (0.60 vs. 0.41; P < 0.01). The reduction in ADFI in LW sows during the hot season was mainly related to a reduction in feed intake during the day rather than during the night (-1.3 vs. -0.2 kg; P < 0.01). Duration of standing was not affected by breed or season, and it averaged 120 min/day. This study confirms the negative effect of the hot season on feeding behavior of lactating sows. It also suggests a better acclimation to daily high temperatures and a greater heat tolerance in CR compared with LW sows, at least for eating behavior.     

Effects of exposure to high ambient temperature and dietary protein level on performance of multiparous lactating sows

Fifty-nine multiparous Large White x Landrace sows were used to determine the effects of high ambient temperature and level of dietary heat increment on lactation and reproductive performance. During a 28-d lactation and the 14-d postweaning period, ambient temperature was maintained constant at 20 or 29 degrees C. Experimental diets fed during lactation were a control diet (NP; 17.6% crude protein) and two low-protein diets obtained by reduction of CP level (LP; 14.2% CP) and both reduction of CP and addition of 4% fat (LPF; 15.2% CP); the NE:ME ratio was 74.3, 75.6, and 75.8% for NP, LP, and LPF diets, respectively. All diets provided 0.82 g of digestible lysine/MJ of NE, and ratios between essential amino acids and lysine were above recommendations. During the ad libitum period (i.e., between d 7 and 27 of lactation), ADFI and NE intake decreased, respectively, from 7.63 to 4.22 kg and 82.0 to 43.3 MJ of NE when the temperature increased from 20 to 29 degrees C. Exposure to 29 degrees C reduced litter BW gain (2,152 vs 2,914 g/d) and increased lactation BW loss (34 vs 16 kg) but increased postweaning BW gain (2 vs - 4 kg). Expressed per kilogram of feed intake, water intake increased from 4.0 to 7.5 L between 20 and 29 degrees C. Compared with the NP diet, low-CP diets (LP or LPF) maintained performance and reduced total N excretion (-22.5%) in lactating sows at thermoneutrality and attenuated the negative effects of high temperature on NE intake and BW loss (40.9 vs 47.9 MJ of NE/d and 41 vs 30 kg for NP and LP + LPF diets, respectively). Temperature and diet composition did not affect the reproductive performances, and the mean weaning-to-estrus interval was 4.9 d. The respiratory rate and skin, udder, and rectal temperatures increased markedly at 29 degrees C (105 vs 33 breaths per min and 37.8 vs 36.1 degrees C, 38.9 vs 38.2 degrees C, and 39.5 vs 38.8 degrees C, respectively) without any effect of diet. In conclusion, low heat increment diets (i.e., with reduced CP/NE ratio) did not affect lactation performance of sows at thermoneutrality and attenuated the effects of high ambient temperature on energy intake and BW loss. At any ambient temperature, N excretion can be markedly reduced.     

Effects of dietary glucose level during late gestation on litter performance and glucose concentration in sows

The effects of feeding glucose during the 5 days before parturition on litter performance and on glucose concentration in sows were studied. At day 100 of gestation, 130 multiparous sows were assigned to the treatments. Late gestating sows were fed 0 g, 150 g, 250 g, 350 g and 450 g of glucose a day, respectively. During lactation, all sows were given free access to the same lactation diet (without glucose). One day before parturition, blood samples were collected from 30 sows (6 sows per treatment) at 10 before and 20, 40, 60 and 80 min after the meal. The supply of additional dietary glucose increased piglet birth weight ( P  < 0.05). Feed intake in week 1 and week 1–4 of lactation was greatest in sows fed the 0% glucose diet, least by sows fed the 18% glucose diet, and intermediate by sows fed the 6, 10, 14% glucose diets ( P  < 0.05). Basal glucose concentration and time of maximum glucose concentration after glucose intake were not affected by dietary treatment in the last 5 days of gestation. The sows fed the 14 and 18% glucose diets had greater maximum increase in glucose concentration than sows fed diet without glucose ( P  < 0.05). In conclusion, feeding glucose to sows during 5 days before parturition increased birth weight of live-born piglet and decreased sows feed intake during lactation, but did not affect the performance of sows and piglets.     

Energy balances of lactating sows in relation to feeding level and stage of lactation

Twelve crossbred sows were used in an energy balance study to estimate energetic efficiency of milk production from feed. Balances were made from 7 to 14 d and from 18 to 25 d of lactation. Two feeding levels were applied (high and low). The low level (L) was meant to supply energy slightly above maintenance, with energy needed for milk to be derived from body reserves. The high level (H) was meant to supply sufficient energy for maintenance and for milk production. The low-level animals received 2.5 to 2.6 kg of feed/d and the high level animals 4.8 to 6 kg/d. The loss of weight of sows during lactation depended more on feeding level than on stage of lactation. A high level of feeding to sows resulted in heavier piglets compared with the low feeding level (significant after 10 d). At 24 d of age piglets with the high-feeding-level sows weighed 7.5 kg and those with the low-level sows, 5.7 kg. At the high level, animals excreted 1,200 to 2,800 kcal more milk energy per day than the low-level animals. Energy for milk from feed was produced with an efficiency of 67 to 69% with a maintenance requirement of 112 to 125 kcal metabolizable energy (ME) X W-.75 X d-1. Efficiency of milk production from feed was calculated as 62% and the maintenance requirement was 68 kcal. In this calculation, milk was corrected toward zero energy balance. Another way of calculating this efficiency after correcting feed toward zero energy balance resulted in estimates of 68% for efficiency and of 88 kcal ME X W-.75 X d-1 for maintenance requirement. From these data it was derived that, for each piglet, the sow needed to receive .5 to .6 kg of extra feed (ME content 3,000 kcal/kg) per day to cover milk production. Level of metabolic rate for nursing piglets was estimated as 97 kcal ME X W-.75 X d-1 for maintenance and, in addition, .195 kcal/kcal extra of milk intake above maintenance.     

Colostrum yield and litter performance in multiparous sows subjected to farrowing induction

The consumption of colostrum at a low level can compromise the survival and growth of piglets. Therefore, this study aimed to evaluate the effect of farrowing induction on colostrum yield, IgG concentration and the survival and performance of piglets until the weaning. Sows of parity 3 to 7 were assigned into two groups: Control (n = 48), sows with spontaneous farrowing; and induction (n = 48), sows induced to farrow on day 114 of gestation with a PGF₂ analogue. Colostrum and blood samples were collected from the sows, at farrowing and 24 hr later. Blood samples from the piglets were collected at 24 hr after birth. The performance of the piglets was evaluated in a subsample of 28 litters from each group. All piglets were weighed at 7, 14 and 20 days of age. The farrowing length, the number of piglets born alive, stillborn piglets, weight at birth, litter weight at birth and colostrum yield were not significantly affected (p > .05) by farrowing induction. There was no difference between the groups (p > .05) in the percentage of sows with obstetric interventions. Serum IgG concentration, in both sows and piglets, and colostrum IgG concentration were similar between the groups (p > .05). Furthermore, survival rate, piglet weight and litter weight at 7, 14 and 20 days of age were also similar between the groups (p > .05). Therefore, it can be concluded that the farrowing induction performed on day 114 of gestation does not affect the colostrum yield, the IgG concentration in colostrum and serum of piglets, and the litter performance until the weaning.     

Photoperiod influences the immune status of multiparous pregnant sows and their piglets

Manipulation of photoperiod may provide a noninvasive, easily implemented, effective method to improve immune status and enhance the efficiency of production. The objective of this study was to evaluate the impact of manipulation of photoperiod on endocrine and immune responses of pregnant sows and their offspring. At d 83 of gestation, sows were moved to gestation stalls and kept on a photoperiod of 12 h of light:12 h of dark until d 90, when sows were assigned to a long day (LD; 16 h of light/d) or a short day (SD; 8 h of light/d) treatment. During farrowing and lactation, one-half of the sows remained on their initial photoperiod (LD:LD or SD:SD), whereas one-half were switched to the opposite treatment (LD:SD or SD:LD). Blood samples were collected from sows at d 0, 7, 14, and 21 posttreatment, 24-h postfarrowing, and the end of lactation (approximately d 21 postfarrowing). Piglets were bled at 7 and 21 d of age for immune measures. Relative to sows on LD, sows on SD had greater concanavalin A- (P = 0.003) and lipopolysaccharide- (P = 0.02) induced proliferative responses at d 7 but reduced responses at d 14. Compared with SD, sows on LD had a greater (P < 0.05) percentage of neutrophils and fewer (P < 0.05) lymphocytes at d 7, resulting in a greater (P = 0.05) neutrophil:lymphocyte ratio. Neutrophil phagocytosis was greater at d 21 in sows kept on LD. Cortisol concentrations tended to be greatest (P = 0.10) in sows on SD:SD at 24-h postfarrowing and throughout lactation. At 7 d of age, piglets on LD:SD had greater (P = 0.001) total white blood cells (WBC) and plasma cortisol (P = 0.001) relative to those on the other photoperiod treatments. Plasma immunoglobulin G was less (P = 0.001) in piglets from sows kept on SD:LD compared with the other photoperiod treatments. Piglets from sows kept on LD:LD tended to have lower total WBC (P = 0.08) at 21 d of age. Piglets from sows kept on SD:SD had greater concanavalin A- (P < 0.001) and lipopolysaccharide-induced (P < or = 0.10) proliferation responses and cortisol (P = 0.05). Phagocytosis was greater (P < 0.003) in piglets from sows that were kept on LD:LD. Cortisol (P = 0.02), WBC (P = 0.003), and immunoglobulin G (P = 0.001) were all influenced by gestational photoperiod treatment. These data indicate that photoperiod influences the immune status and endocrine response of piglets from dams that have been kept on a defined photoperiod. We conclude that photoperiod effects on piglets may be programmed in utero and can last throughout lactation.     

Energy balance of lactating primiparous sows as affected by feeding level and dietary energy source

The effects of feeding level and major dietary energy source used during lactation on sow milk composition, piglet body composition, and energy balance of sows were determined. During a 21-d lactation, 48 primiparous sows were fed either a Fat-rich (134.9 g/kg fat; 196.8 g/kg carbohydrate) or a Starch-rich (33.2 g/kg fat; 380.9 g/kg carbohydrate) diet at either a High (44 MJ NE/d; 1,050 g protein/d) or a Low (33 MJ NE/d; 790 g protein/d) feeding level. Within each feeding level, the two diets were fed to provide an isocaloric and isonitrogenous intake. At the Low feeding level, no differences in milk production, milk composition, or piglet body composition were found as a result of feeding the two dietary energy sources. However, at the High feeding level, sows fed the Fat-rich diet produced higher milk fat (8.4 vs 6.9%) and milk energy (5.38 vs 4.77 kJ/g) concentrations and a higher piglet body fat concentration (152.1 vs 135.4 g/kg) than sows fed the Starch-rich diet. At the Low feeding level, the energy balance (d 6 to d 20) of the sows was similar when fed either the Fat- or the Starch-rich diet (-558 and -515 kJ x BW(-.75) x d(-1)), but at the High feeding level, the energy balance was more negative in sows fed the Fat than those fed the Starch-rich diet (-544 vs -372 kJ x BW(-.75) x d(-1)). This suggests that at the High feeding level, dietary energy in the form of fat is preferentially used for milk fat synthesis, resulting in growth and in fatter piglets. Alternatively, at the High feeding level, Starch as the major energy source is used only for growth of the piglets, as confirmed by protein deposition, and also results in a less-negative energy balance for the sows. From this experiment, it can be concluded that effects of substituting cornstarch for fat in the diet of lactating sows on milk composition, piglet body composition, and energy balance of the sows are dependent on feeding level.     

Evidence that oxidative stress is higher in replacement gilts than in multiparous sows

The recent success obtained in term of increasing the litter size of sows has not correlated with a reduction of replacement rate. There is thus an increased economic demand for gilts with optimal reproductive potential and longevity. Unfortunately, replacement gilts are known to be more susceptible to diseases and less productive than multiparous sows. Interestingly, reproductive performance, resistance to diseases and longevity could all be largely affected by oxidative stress. To investigate whether oxidative stress conditions could account for the poor longevity of gilts, three distinct groups of conventional Yorkshire × Landrace sows were formed based on their similar age and parity (gilts, second parity sows as well as fourth to fifth parity sows). All animals were slaughtered during the post‐ovulatory period, and blood as well as tissue samples were collected. Biomarkers of oxidative damage to proteins (carbonyls) and DNA (8‐OHdG) were analysed in samples. Specific mRNA expression of major antioxidants such as glutathione peroxidases 1, 3 and 4 (GPx1, GPx3, GPx4) as well as superoxide dismutases 1 and 2 (Sod1, Sod2) were monitored in liver and kidney samples by quantitative RT‐PCR. Specific enzymatic activities of both GPx and SOD were measured by spectrophotometric assays. The plasma concentration of protein carbonyls was significantly different between the three groups with the highest concentration being observed in gilts (p ≤ 0.001). The mRNA expression levels of GPx1 and GPx4 were also significantly increased in the liver of gilts when compared to multiparous sows (p ≤ 0.05). SOD2 enzymatic activity was found to be higher in the liver of gilts than multiparous sows (p ≤ 0.05). Taken together, these results indicate that replacement gilts sustain significantly higher oxidative conditions than multiparous sows. Current findings may contribute to the design of nutritional regimens that will increase the productivity of gilts by counteracting oxidative stress.     

Influence of high ambient temperatures on performance of multiparous lactating sows.

Multiparous Large White sows (n = 63) were used to investigate the effects of five ambient temperatures (18, 22, 25, 27, and 29 degrees C) and two dietary protein contents on their lactation performance. At each temperature treatment, ambient temperature was maintained constant over the 21-d lactation period. Dietary protein content was either 14 or 17% with essential amino acids levels calculated not to be limiting. The animals had ad libitum access to feed between the seventh and the 19th day of lactation. Diet composition did not influence lactation performance. Over the 21-d lactation, feed intake decreased from 5.67 to 3.08 kg/d between 18 and 29 degrees C. Between d 7 and 19, the corresponding values were 7.16 and 3.48 kg/d, respectively. This decrease was curvilinear; an equation to predict voluntary feed intake (VFI) from temperature (T, degrees C) and body weight (BW, kg) is proposed: VFI = -49,052 + 1,213 T - 31.5 T2 + 330 BW - .61 BW2 (residual standard deviation: 1,018). Skin temperature increased regularly with increased ambient temperature (34.6 to 37.4 degrees C between 18 and 29 degrees C), whereas udder temperature reached a plateau at 25 degrees C (38.3 degrees C). The gradient of temperature between skin and rectum was minimal (2 degrees C ) at 27 degrees C and remained constant at 29 degrees C. This constancy coincides with the marked reduction of feed intake. The respiratory rate increased from 26 to 124 breaths/min between 18 and 29 degrees C, and this indicates that the evaporative critical temperature was below 22 degrees C. The BW loss increased from 23 to 35 kg between 18 and 29 degrees C, but its estimated chemical composition remained constant. Pig growth rate was almost constant between 18 and 25 degrees C (241 g/d) and was reduced above 25 degrees C (212 and 189 g/d at 27 and 29 degrees C, respectively). In conclusion, temperatures above 25 degrees C seem to be critical for lactating sows in order to maintain their performance.     

Effects of dietary fiber on performance of multiparous lactating sows in a tropical climate

Sixty-two multiparous Large White sows were used to determine the effect of dietary fiber level on lactation performance according to season under conditions of a humid tropical climate. This experiment was conducted in Guadeloupe (West French Indies, lat 16 degrees N, long 61 degrees W) between October 1999 and January 2001. Two seasons were distinguished a posteriori from climatic measurements parameters continuously recorded in the farrowing room. During the warm season, ambient temperature and relative humidity averaged 25 degrees C and 86.8%, respectively. The corresponding values for the hot season were 27.5 degrees C and 83.5%. Experimental diets fed during lactation were a control diet (C; 14% neutral detergent fiber) and a high-fiber diet (HF; 20% neutral detergent fiber) obtained by substitution of wheat middlings by wheat bran. The two diets were formulated to provide the same ratios between essential amino acids and lysine and between lysine and net energy. No interaction between season and diet composition was found for all criteria studied. Over the 28-d lactation, average daily feed intake (ADFI) was lower and body weight loss was higher (P < 0.001) during the hot season compared to the warm season (3,447 vs 4,907 g/d and 33 vs 17 kg, respectively). The number of stillborn piglets was higher (P < 0.05) during the hot season than during the warm season (2.0 vs 1.1 piglets, respectively). Litter growth rate and mean BW of piglets at weaning were reduced (P < 0.01) during the hot season vs the warm season (2.1 vs 2.3 kg/d and 7.7 vs 8.3 kg, respectively). The ADFI was similar for both diets and digestible energy (DE) intake tended to be lower (P = 0.06) with the HF diet (54.9 vs 59.3 MJ of DE/d for C sows) in relation with its lower DE concentration. The body weight loss was greater (P < 0.01) for HF sows than for C sows (30 vs 21 kg). Compared with the C diet, the HF diet increased (P < 0.05) litter growth rate and piglet body weight at weaning (2.3 vs 2.1 kg/d and 8.3 vs 7.7 kg/d for HF vs C, respectively). Season and diet composition did not affect the weaning-to-estrus interval. In conclusion, the hot season in humid tropical climates, which combines high levels of temperature and humidity, has a major negative effect on the performance of lactating sows.     

Split-weaning before altrenogest synchronization of multiparous sows alters follicular development and reduces embryo survival

This study used split-weaning (SW) to induce differences in follicle size at weaning and study its consequences for follicle development during and after post-weaning altrenogest feeding and for reproductive performance. Multiparous sows (n=47) were assigned to SW (n=23; litter size reduced to the six smallest piglets 3 days before weaning) or control (C; n=24; normal weaning). Altrenogest (20 mg/day) was fed to all 47 sows from Day -1 till Day 5 (complete weaning = Day 0). Follicle size on Day 1, 2 and 8 was smaller in C than in SW (p ≤ 0.05). Ovulation rate was similar, but C sows had higher embryo survival rate (ESR) than SW sows (83 ± 19 and 58 ± 31%, respectively; p=0.001). SW sows with low ESR (<63%; n=10) had a greater follicle size on days 3-6 than SW sows with high ESR (>63%; n=10; p ≤ 0.04). A decrease in follicle size between Day 5 and 6 of altrenogest feeding was associated with increased ESR in both treatments (p=0.002). Follicle pool analyses (assessment of all follicles >2 mm) revealed that on Day 3, sows with low ESR had a higher % of follicles >5 mm compared with sows with high ESR (30% vs 10%; p=0.04). Thus, sows in which follicle growth was less suppressed during altrenogest feeding had a lower ESR. These effects on follicle development and ESR were more pronounced in split-weaned sows.     

Different dietary methionine to lysine ratios in the lactation diet:effects on the performance of sows and their offspring and methionine metabolism in lactating sows

Background: Over the last decade, the nutritional requirements of lactating modern genotype sows have increased. The current nutritional recommendations might be unable to meet the needs of increased litter size and milk production, and thus the nutritional requirements need to be re-evaluated. The current study was conducted to investigate the effects of dietary methionine to lysine(Met:Lys) ratios on the performance of and methionine metabolism in lactating sows.Results: During the 1~(st) week of lactation, piglets reared on sows in the 0.37 to 0.57 Met:Lys ratio groups grew faster than those reared on sows in the control group(0.27)(P 0.01). The 0.37-ratio group showed increased levels of GSHPx in plasma during lactation(P 0.01) and decreased concentrations of urea nitrogen in the plasma of sows(P 0.05).Compared with the 0.27-ratio group, the levels of T-AOC and GSH-Px in the plasma and homocysteine in the milk of lactating sows were significantly increased in sows in the 0.47-ratio group(P 0.01). In sows fed a 0.57-ratio diet, the levels of glutathione and taurine in the plasma and milk were improved significantly during lactation. However, the content of TBARS in the blood(P 0.05 at day 7 and P = 0.06 at weaning day) was increased(P 0.01). Moreover, there were linear increases in the levels of homocysteine in the blood and milk of sows during the lactation period(P 0.01)with increased dietary Met:Lys ratios in the lactation diet.Conclusions: The current study indicated that increasing the dietary Met:Lys ratio(0.37～0.57) in the lactation diet had no significant effect on the overall performance of sows or the colostrum and milk composition, but it increased piglet mean BW and piglet ADG during the first week of lactation. Increasing dietary methionine levels had no significant effect on antioxidant function in lactation sows, even though it increased levels of GSH and GSH-Px in the plasma of sows during lactation. However, the content of homocysteine in the plasma and milk increased during lactation due to a high level of dietary methionine.