Effects of beet pulp supplementation on growth performance,fecal moisture,serum hormones and litter performance in lactating sows

This study was conducted to evaluate effects of beet pulp supplementation on growth performance, fecal moisture, serum hormones and litter performance in lactating sows. Ninety primiparous sows (Landrace × Yorkshire) were randomly allotted to one of three dietary treatments in a 21‐day trial starting 3 days before parturition. The three dietary treatments were supplemented with 0, 10 and 20% beet pulp, respectively. Backfat loss and fecal moisture content were increased (P < 0.05), where cortisol and norepinephrine levels were decreased (P < 0.05) in sows fed beet pulp supplementation diets compared with control diet, but there was no difference between 10% and 20% beet pulp supplementation treatments. No effect was observed on bodyweight, average daily intake, weaning to estrus interval, epinephrine level in sows and litter weight, litter size, survivability in piglets among dietary treatments. Taken together, beet pulp supplementation has no significant effect of growth performance of lactating sows and piglets with decreased cortisol and norepinephrine levels in lactating sows, but it can increase fecal moisture content which is beneficial for sow feces excretion.     

Effect of placenta feeding to sows on plasma biochemical composition and growth of their piglets

The objective of the present study was to investigate the effects on the plasma biochemical composition and growth of piglets of placenta‐fed sows. The experimental animals were a total of 21 sows (L × LW) of third parity, and each sow was suckled by 11 ± 1 piglets. Sows fed without placenta were considered as the control (C), treatment 1 (T1) were placenta‐fed from days 1–7 after farrowing and treatment 2 (T2) were placenta‐fed from day 7 before farrowing to day 7 after farrowing. Glucose of piglets was lower (P < 0.05) in T2 than C and T1 on day 10. Total cholesterol of piglets was higher (P < 0.05) in T2 than C on day 4. Fe of piglets was higher (P < 0.05) in T2 than C on days 4, 20 and 30. Unsaturated iron‐binding capacity was lower (P < 0.05) in T2 than C on days 4 and 30. Immunoglobulin G of piglets was higher (P < 0.05) in T1 and T2 than C on days 4 and 10. Daily gain of piglets was higher (P < 0.05) in T1 than C and T2 on day 4 when daily gain was calculated. Total daily gain increased (P < 0.05) by prolongation of placenta feeding period. The results indicate that feeding placenta to sows may improve the plasma biochemical composition and growth of their piglets.     

Effect of ginseng polysaccharides on the immunity and growth of piglets by dietary supplementation during late pregnancy and lactating sows

There are many reports that dietary supplementation with plant polysaccharides in pigs might promote their growth, but little is known about the maternal effect of ginseng polysaccharides (GPS) on piglets’ growth by dietary supplementation to pregnant and lactating sows. In the current study, the effects of dietary supplementation with GPS on the immunity of sows and growth of their piglets were investigated. Results showed no significant difference among the four groups in the total number of piglets, live piglets, weak piglets and birth weight of piglets, indicating the GPS‐treatment has no adverse effect on reproduction. Furthermore, the weaning weight of the GPS‐treated groups was higher than that of control group (P < 0.05); among them, the addition of 200 mg/kg dose has the best effect. Interestingly, GPS increased the total immunoglobulin G concentration in milk and serum of sows (P < 0.05). The concentrations of interleukin (IL)‐2, IL‐6, tumor necrosis factor (TNF)‐α, and interferon‐γ in milk and serum of sows were also increased in the experimental groups relative to the control (P < 0.05). Meanwhile, maternal supplementation of GPS significantly increased IL‐2 and TNF‐α concentration in the piglets’ serum of the experimental groups relative to control (P < 0.05). GPS (200 mg/kg) significantly increased the glutathione peroxidase activity in milk and serum (P < 0.05), while the concentrations of malondialdehyde were significantly reduced (P < 0.05). The present results indicated that GPS supplementation during late pregnancy and lactation improved immunity‐related bio‐molecular levels in sow serum and milk, which may be further beneficial to piglet health and growth through biological transmission effects.     

Effects of different n‐6 to n‐3 polyunsaturated fatty acids ratio on reproductive performance,fecal microbiota and nutrient digestibility of gestation‐lactating sows and suckling piglets

This study was conducted to evaluate the effects of dietary ratios of n‐6:n‐3 polyunsaturated fatty acids (PUFA) on reproductive performance, fecal microbiota and nutrient digestibility of gestation‐lactating sows and suckling piglets. Fifteen primiparous sows (Landrace × Yorkshire) were randomly allotted into three treatments. Fed diets contained different ratios of n‐6:n‐3 PUFA, including 20:1, 15:1 and 10:1. No differences were detected among the treatments for average daily feed intake (ADFI) of sows and the back fat levels during lactation (P > 0.05). Body weight (BW) loss of sows after farrowing to weanling was greater in the 10:1 treatment compared with 15:1 or 20:1 (P < 0.05). In piglets, a great significant difference for BW was observed at 4 weeks (P < 0.01). Furthermore, average daily gain (ADG) of piglets in the 10:1 treatment was higher (P < 0.05). No difference was observed among treatments in nutrient digestibility of sows (P > 0.05). A great significant difference for fecal microbiota was in the 10:1 treatment compared with 20:1 and 15:1 treatments (P < 0.01). In conclusion, altering the ratio of n‐6:n‐3 PUFA in gestation‐lactating sow diet had no difference on nutrient digestibility in gestation‐lactating sows, but it can partially improve reproductive performance.     

不同形式补铁补硒对仔猪生长性能、血液生化指标、免疫性能的影响

[目的] 比较母猪和仔猪不同形式的补铁补硒对仔猪生产性能、血液生化指标、免疫性能的影响。[方法] 将32头母猪随机分为8组,每组4头,1~4组基础日粮中添加硫酸亚铁和亚硒酸钠,5~8组基础日粮中添加甘氨酸螯合铁和硒代蛋氨酸。2组和6组母猪所产仔猪于3日龄肌注铁硒合剂;3组和7组仔猪基础日粮中添加硫酸亚铁和亚硒酸钠;4组和8组仔猪基础日粮中添加甘氨酸螯合铁和硒代蛋氨酸;1组和5组仔猪饲喂基础日粮,不接受任何形式的补铁补硒。母猪预产期前30 d开始饲喂试验日粮,仔猪7日龄时开始饲喂试验日粮,试验至仔猪21日龄断奶结束。测定并比较不同组别仔猪生长性能指标、血液生化指标以及免疫性能指标,以及不同组别母猪初乳和常乳中的铁硒含量。[结果] 在仔猪补铁补硒形式相同的条件下,母猪基础日粮中添加甘氨酸螯合铁和硒代蛋氨酸（5~8组）与基础日粮中补充硫酸亚铁和亚硒酸钠（1~4组）相比,能够显著（P<0.05）或极显著（P<0.01）提高仔猪的初生重、断奶重、断奶存活率、断奶合格率,2日龄和21日龄血浆铁含量、血浆硒含量、血红蛋白含量、血浆转铁蛋白含量、IgA含量、IgG含量、IgM含量,以及母猪初乳和常乳中的铁硒含量;在2种形式的母猪补铁补硒条件下,与不补铁补硒相比,仔猪不同补铁补硒形式（2~4组和6~8组）对其断奶重、断奶存活率、断奶合格率,以及21日龄血浆铁含量、血浆硒含量、血红蛋白含量、血浆转铁蛋白含量、谷胱甘肽过氧化物酶活性、IgA含量、IgG含量、IgM含量均有极显著（P<0.01）的提高作用,并且仔猪基础日粮中添加甘氨酸螯合铁和硒代蛋氨酸的效果优于肌注铁硒合剂和基础日粮中补充硫酸亚铁和亚硒酸钠。[结论] 母猪和仔猪基础日粮中添加甘氨酸螯合铁和硒代蛋氨酸,能有效提升仔猪的生长性能、血液生化指标和免疫性能。     

Exposure to maternal feces in lactation influences piglet enteric microbiota,growth, and survival preweaning

It is known that gilt progeny performance is reduced compared with sow progeny. Previous research suggests that the presence of maternal feces in early life improves the health and survival of offspring. Therefore, we aimed to determine whether contact with feces from multiparous (MP) sows would improve the growth and survival of piglets born and reared on primiparous (P1) sows and if so, whether these differences are associated with the gut microbiota. Four treatments were applied for 10 days: Donor (n = 29) piglets had limited access to maternal feces as, each morning, sow feces were removed and placed in the crate of a P1 sow (P1-FT; n = 30 piglets) and P1-Con (n = 29) and MP-Con (n = 33) piglets had access to their own mothers’ feces. All piglets were weighed on days 1, 3, 10, and 18. Fecal samples were collected from a subset of sows (n = 10/treatment) 3 days post farrow and from two female piglets/litter on days 10 and 18 (n = 20/treatment) and subject to 16S rRNA amplicon analysis. Escherichia, Clostridium, Campylobacter, and Treponema were more abundant in MP sows, while P1 sows had a higher abundance of Lactobacillus and Prevotella. At 10 days, P1 progeny fecal microbiota differed, and growth and survival were reduced when compared with MP progeny. No treatment effect was observed for P1-FT piglets (P > 0.05). Donor piglets had a different fecal microbiota and improved weight and survival then all other treatments (P < 0.05). Overall, the removal of sow feces from the farrowing crate improved piglet microbiota development, growth, and survival.     

Impairment of the Peripheral Lymphoid Compartment in Iron‐deficient Piglets

The aim of this study was to investigate the effect of neonatal iron deficiency on immune functions in young piglets. While control piglets were not given any iron preparation until the age of 21 days, another group of piglets was given 200 mg of Fe³⁺‐dextran i.m. on day 3. Red blood cell parameters in the former, iron‐deficient group were characteristic of hypochromic anaemia. In addition, the total leucocyte count (P < 0.01), relative and absolute neutrophil count (P < 0.01) and absolute lymphocyte count (P < 0.05) in peripheral blood were found significantly lower in iron‐deficient piglets than in their iron‐supplemented counterparts. Lymphocyte activity as measured by in vitro lymphocyte transformation test was impaired in iron‐deficient piglets. A statistically significant decrease in circulating B‐lymphocyte numbers was found in non‐supplemented animals. Iron deficiency apparently negatively influenced the immunocompetence in piglets.     

血红素铁对断奶仔猪生长性能和血液指标的影响

选取120头28日龄断奶仔猪,随机分成4个处理组,即1个对照组和3个试验组,每组3个重复,每个重复10头。对照组饲喂基础日粮,试验1、2、3组分别饲喂基础日粮中血红素铁净添加量为27.5、55.0、85.0 mg/kg的3种试验日粮,研究日粮中添加血红素铁对断奶仔猪的生长性能、血液指标(血红蛋白浓度、免疫球蛋白浓度)的影响。试验正试期13 d。结果表明,血红素铁各添加量组均能够提高仔猪的生长性能,日粮中血红素铁添加量为55 mg/kg时,仔猪平均日增重、饲料转化率较对照组分别提高12.02%和10.27%(P<0.05)。血红素铁对断奶仔猪有良好的促生长作用,也在一定程度上提高了仔猪血液中血红蛋白和IgG浓度。     

复合有机铁对母猪繁殖性能和仔猪生长性能的影响

通过在怀孕后期和哺乳期母猪日粮中添加不同水平的硫酸亚铁和复合有机铁,以及肌注铁与否来考察复合有机铁对母猪繁殖性能和仔猪生长性能的影响。结果表明,与无机铁相比,母猪饲粮中添加复合有机铁可提高母猪产活仔率和断奶仔猪存活率,提高仔猪10日龄、21日龄体重;综合铁源、铁水平以及肌注补铁的效应,添加120 mg/kg复合有机铁,同时仔猪均辅以肌注补铁,可显著提高仔猪肌注7日龄和断奶时体重(P<0.05)。     

饲粮铁水平对妊娠母猪繁殖性能和生化参数的影响

30头妊娠母猪随机分为3组,研究了饲粮不同铁水平对其繁殖性能的影响。结果表明,饲粮铁水平200mg/kg组和300mg/kg组与100mg/kg组相比,妊娠母猪90d血清孕酮水平、所生仔猪初生重、仔猪（生后不补铁）断奶重、新生仔猪血红蛋白量和红细胞数都有不同程度的提高;母猪血清含量和仔猪肝脏铁含量也有不同程度的提高。上述提示,适度提高母猪饲粮铁水平能改善母猪的繁殖性能和预防仔猪贫血。     

Effects of the standardized ileal digestible valine : lysine ratio on performance,milk composition and plasma indices of lactating sows

To determine the effects of standardized ileal digestible (SID) valine : lysine ratio on the performance, milk composition and plasma indices of lactating sows, 32 Large White × Landrace sows (219.78 ± 7.15 kg body weight; parity 1.82 ± 0.62) were allotted to one of four dietary treatments with eight sows per treatment based on parity, back fat thickness and body weight. The sows were fed corn‐soybean meal‐based diets containing 63, 83, 103 or 123% SID valine : lysine from day 107 of gestation until day 28 of lactation. The average daily feed intake of sows and daily weight gain of piglets increased linearly (P < 0.05) while back fat loss decreased linearly (P < 0.05) as the SID valine : lysine ratio increased. All of the analyzed amino acids in sow colostrum and valine concentrations of sow and piglet plasma increased linearly (P < 0.05) with the increasing SID valine : lysine ratio. In conclusion, 88 and 113% dietary SID valine : lysine ratios were optimal to achieve minimum back fat loss and maximum piglet growth rate using a linear‐break point model which exceeds the requirement of 85% that is estimated by the National Research Council (2012).     

Effects of Inulin Supplementation in Low‐ or High‐Fat Diets on Reproductive Performance of Sows and Antioxidant Defence Capacity in Sows and Offspring

This experiment was conducted to investigate the effects of inulin supplementation in low‐ or high‐fat diets on both the reproductive performance of sow and the antioxidant defence capacity in sows and offspring. Sixty Landrace × Yorkshire sows were randomly allocated to four treatments with low‐fat diet (L), low‐fat diet containing 1.5% inulin (LI), high‐fat diet (H) and high‐fat diet containing 1.5% inulin (HI). Inulin‐rich diets lowered the within‐litter birth weight coefficient of variation (CV, p = 0.05) of piglets, increased the proportion of piglets weighing 1.0–1.5 kg at farrowing (p < 0.01), reduced the loss of body weight (BW) and backfat thickness (BF) during lactation (p < 0.05) and decreased the duration of farrowing as well as improved sow constipation (p < 0.05). Sows fed fat‐rich diets gained more BW during gestation (p < 0.01), farrowed a greater number of total (+1.65 pigs, p < 0.05) and alive (+1.52 pigs p < 0.05) piglets and had a heavier (+2.06 kg, p < 0.05) litter weight at birth as well as a decreased weaning‐to‐oestrous interval (WEI, p < 0.01) compared with sows fed low‐fat diets. However, it is worth noting that the H diet significantly decreased the serum activities of superoxide dismutase (T‐SOD) and glutathione peroxidase (GSH‐Px) and increased the serum malondialdehyde (MDA) levels in sows and piglets (p < 0.05). In contrast, HI diet enhanced the activities of T‐SOD and GSH‐Px and decreased the serum MDA concentrations (p < 0.05) in sows and piglets. In summary, the fat‐rich diets fed to sows during gestation had beneficial effects on reproductive performance, but aggravated the oxidative stress in sow and piglets. Inulin‐rich diets fed to sow during gestation had beneficial effects on within‐litter uniformity of piglet birthweight and enhanced the antioxidant defence capacity of sows and piglets.     

Effects of temperature and temperature‐humidity index on the reproductive performance of sows during summer months under a temperate climate

Heat stress is known to influence sow reproduction, but it is unknown to which extent under temperate climates. Therefore, the impact of temperature and temperature‐humidity index (THI) on the reproductive performance of sows during summer months from 2009 to 2011 were studied. Reproductive parameters of 22 264 inseminations and 21 610 resulting farrowings of 22 German commercial farms were analyzed. Climatic records were available from the nearest weather station. Effects of temperature and THI at different periods of the reproductive cycle were estimated from May to September where temperatures were expected to influence climatic conditions indoors. High temperatures and THI values 5 days pre‐ and 14 days post‐breeding reduced litter size by 0.01 to 0.03 piglets (P < 0.05). Prior to farrowing, the number of liveborn piglets was reduced (P < 0.05) and of stillborns increased with rising climatic variables (P < 0.001). On the day of farrowing, reduced numbers of weaned piglets were observed when temperature and THI values were elevated (P < 0.05), but pre‐weaning mortality was not influenced (P > 0.05). In conclusion, even under temperate conditions adverse effects of climatic variables on the reproductive performance of sows are present. Thereby, the number of liveborn piglets can be considered as the most sensitive parameter to heat stress. Considering the impact of climate change and predicted heat waves, strategies to mitigate the impact of heat stress are necessary.     

Effects of different gestation housing types on reproductive performance of sows

This study evaluated the effects of different gestation housing types on reproductive performance of sows. A total of 60 sows (218 ± 24 kg body weight) with mixed parity were used. During gestation, 28 sows were housed in groups with electronic sow feeders (space allowance = 1.26 m²/sow) and 32 sows were housed in individual stalls (space allowance = 1.20 m²/sow). Sows from both housing types were moved to farrowing crates on day 109 of gestation and stayed until weaning (18 days post‐farrowing). Typical corn‐soybean meal diets were provided to sows during gestation and lactation. Measurements were reproductive performance of sows at farrowing as well as performance of sows and their litter during lactation. Similar total numbers of piglets born at farrowing were observed for sows gestated in both housing types. However, group‐housed gestation sows had more mummies (0.321 vs. 0.064; P < 0.05) and stillbirths (0.893 vs. 0.469; P = 0.073) at farrowing than individual‐housed gestation sows. Consequently, individual‐housing type had higher percentage of piglets born alive (95.5 vs. 90.4%; P < 0.05) than the group‐housing type. Therefore, improved reproductive performance of sows from individual gestating housing was confirmed in this study.     

Effect of dietary supplementation of oregano essential oils to sows on colostrum and milk composition, growth pattern and immune status of suckling pigs

This study evaluated the effects of supplementing sow diets with oregano essential oils (OEO) during gestation and lactation on sow colostrum and milk composition and on the growth pattern and immune status of suckling pigs. A total of 70 second-parity sows were randomly assigned to 1 of 2 gestation dietary treatments within 24 h after service: control (CON) or CON + 250 mg/kg of OEO (OREG). In lactation, sows were again assigned to either the CON or OREG dietary treatment. Thus, the lactation treatments were CON-CON, CON-OREG, OREG-CON, and OREG-OREG. Colostrum and blood samples were collected from 6 sows per lactation dietary treatment. Thymus lymphocyte (T lymphocyte) subpopulations (γδ, cluster of differentiation 8, and 32 cluster of differentiation 4) were enumerated in blood and mammary secretions along with IGF-1, IgG, and IgA concentrations. Piglet growth rate were determined from 18, 17, 17, and 18 litters from the CON-CON, CON-OREG, OREG-CON, and OREG-OREG lactation dietary treatments, respectively. Growth rates were determined in 630 piglets, and piglets were individually identified and weighed on 1, 5, 9, 12, 16, and 19 d of age. Oregano essential oil supplementation during gestation or lactation had no effect (P > 0.05) on GE, CP, GE:CP, GE:fat, and IGF-1 in sow milk. Reductions of the fat percentage in milk on d 7 (P < 0.05) and d 14 (P = 0.07) were found in sows supplemented with OEO during lactation compared with those in the CON treatment. Milk from sows supplemented with OEO during lactation had the greatest number of T lymphocytes compared with those in the lactation CON treatment on d 14 of lactation (P < 0.01). The number of T lymphocytes in milk was greater for sows in the CON-OREG treatment compared with those other treatments on d 14 of lactation (P < 0.05). Energy intake was greater on d 1 to 5 in piglets from sows fed OEO during gestation than those from sows in the CON treatment (P < 0.05). A trend (P = 0.10) for greater milk intake was observed in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment. Similarly, a tendency for an increase in ADG on d 1 to 5 was found in piglets from sows supplemented with OEO during gestation compared with those from sows in the CON treatment (P = 0.10). Insulin-like growth factor-1 at birth and on d 7 and 14 of lactation did not differ among piglets from sows assigned to the different dietary treatments. Oregano essential oil supplementation of sow diets did not affect (P > 0.05) immunoglobulin concentrations in piglets after suckling. Supplementing sow diets with OEO during gestation or lactation did not affect (P > 0.05) the T lymphocytes, percentage of T-lymphocyte subpopulations, and natural killer cell activity of piglets during lactation. Supplementing sow diets with 250 mg/kg of OEO during gestation and lactation did not affect the growth potential of and immune responses in suckling piglets.     

母猪铁代谢与仔猪铁代谢之间的关系与影响

母猪铁代谢与仔猪铁代谢之间有很紧密的关联,近年来关于是否能通过在母猪饲料添加铁来给仔猪补铁做过很多相关研究,得出的结论不尽相同。母猪铁代谢对仔猪的铁代谢有很大的影响,下面就母猪铁代谢与仔猪铁代谢之间的关系和影响进行相关综述讨论,为弄清母猪铁代谢和仔猪铁代谢之间的关系和影响提供一定的参考。     

Fertility of Sows Fed ad libitum with a High Fibre Diet During Pregnancy

The effect of ad libitum (ADLIB) feeding strategy on the fertility of the group housed sow was studied in a prospective field trial during 1.5 years. All study animals farrowed under standard farrowing circumstances in crates, and they were provided with an ad libitum feeding throughout the 30‐day lactation. After weaning, animals were randomly allocated to one of the two dry sow feeding strategies (AD LIB or CONT). After oestrus detection in groups, they were artificially inseminated and moved into pregnancy pens with partially slatted floor, in groups of 40 sows each. The ADLIB sows (n = 447) were loose housed and provided with ad libitum access to 7.7 MJ/kg feed high in fibre from two feeders per group. The control sows (n = 479; CONT) were also loose housed and given a standard dry sow feed in feeding stalls once a day (2.5 kg/day. The energy content of the feed was 9.3 MJ/kg NE). The feeding strategy (ADLIB vs CONT) had no effect on pregnancy rate (85.8 vs 90.9, p > 0.05), weaning to oestrus interval (7.7 vs 7.3 days, p > 0.05), piglets born alive (11.5 ± 3.5 vs 11.6 ± 3.3, p > 0.05), stillborn piglets (1.2 ± 1.8 vs 0.9 ± 1.5, p > 0.05) nor on progesterone concentration (p > 0.05). CONT sows weaned more piglets (9.7 ± 2.2 vs 9.4 ± 2.0, p < 0.01), whereas the piglets of AD LIB sows were heavier at weaning (8.8 ± 0.9 vs 8.0 ± 1.3 kg, p < 0.05). In conclusion, ad libitum feeding with a high in fibre diet during pregnancy did not affect the reproductive performance.     

Influence of dietary fat source on sow and litter performance,colostrum and milk fatty acid profile in late gestation and lactation

The objective of this study was to investigate the effects of dietary supplementation with various fat sources (3.8–3.9% of diet) during late pregnancy and lactation on the reproductive performance, fatty acids profile in colostrum, milk and serum of sow progeny. A total of 80 multiparous sows were randomly fed a control (adding no oil), palm oil (PO), fish oil (FO) or soybean oil (SO) supplemented diet from 90 days of pregnancy to weaning. Supplementation of FO increased litter size of weak piglets, compared with the control‐fed sows (P < 0.05). Dietary FO and SO supplementation, enhanced the weaning survival rate, litter weaning weight, litter weight gain and fat content in milk (P < 0.05). The highest immunoglobulin (Ig)G and IgM levels in colostrum and milk were observed in the FO group (P < 0.05). Meanwhile, the highest concentration of C22:5 (n‐3) and C22:6 (n‐3) in colostrum, milk and piglet serum was observed in the FO group (P < 0.05). Taken together, dietary inclusion of FO or SO improved growth performance of nursing piglets by increasing milk fat output, and FO consumption by sows might benefit the piglets via increasing n‐3 polyunsaturated fatty acid availability and immunoglobulins (IgG and IgM) secretion.     

Comparison of oral versus parenteral iron supplementation on the health and productivity of piglets

The aim of this study was to compare oral iron supplementation in feed with a standard iron injection and assess the impact on the health and productivity of pigs. The reliability of a quick test (HemoCue) for the measurement of blood haemoglobin concentration was also investigated. Three pig herds, with a total of 88 sows and their piglets, were included in the study. Piglets in treatment group O were fed a special iron-rich feed on days 2 to 4, 5 to 7 and 8 to 12 of lactation using a specially designed feeding device. Piglets in group IM received 200 mg of an iron dextran complex intramuscularly at three days of age. Haemoglobin concentrations and performance of the piglets were compared between groups. The mean haemoglobin concentrations in pigs at weaning were 131.4 and 116.4 g/l for pigs in groups O and IM, respectively (P<0.01). Daily weight gain (253.9 v 248.8 g/day) and piglet mortality (11.4 v 12.2 per cent) were slightly better in group O than in group IM (P>0.05).     

Effect of β‐carotene on health status and performance of sows and their litters

A total of 48 sows were allocated to four groups (12 sows per group) at the 99th day of pregnancy and were treated throughout two consecutive breeding cycles, as follows: (a) control group: no treatment; (b) group BC1: 400 mg β‐carotene/sow/day via feed from 7 days prior to the expected farrowing, until the 30th day postservice; (c) group BC2: 400 mg β‐carotene/sow/day via feed from 7 days before weaning up to service, followed by 200 mg β‐carotene until the 30th day postservice; and (d) group BC inj: four intramuscular (i.m.) injections of 200 mg β‐carotene/sow (on the 100th day of pregnancy, on the day of farrowing, on the day of weaning and on the first day of oestrus). Serum β‐carotene equivalents, vitamin A and IgG concentrations were determined in sows at several times of the breeding cycle. Moreover, serum IgG concentrations were determined in piglets on the second day of lactation and at weaning. Data relating to sow reproductive parameters and litter parameters were also recorded. It was shown that concentrations of serum β‐carotene equivalents were elevated only in the BC inj group during lactation and at service, while serum vitamin A concentrations were also elevated in the BC inj group only at oestrus. There was no effect of β‐carotene on the oestrus intensity score, the weaning‐to‐oestrus interval, the number of returns to oestrus per sow and the farrowing‐to‐farrowing interval. The number of piglets born alive was greater in the BC inj group compared with the controls, while the litter size at weaning was greater in the groups BC1, BC2 and BC inj compared with the control group (p < 0.05). Supplementation of β‐carotene did not appear to influence the serum IgG concentration in sows and piglets.