Effects of a dietary crude fibre concentrate on growth in weaned piglets.

Many fibre sources can help the adaptation of piglets at weaning, improving the growth. In this study, the effects of a dietary crude fibre concentrate (CFC) on piglet's growth was investigated. From 31 to 51 days of age, 108 weaned piglets (D×(Lw×L)), had access to two isofibrous, isoenergetic and isonitrogenous diets, supplemented with 1% of CFC (CFC group) or not (control (CON) group). From days 52 to 64 all piglets received the same starter diet. During the dietary treatment period the CFC group showed higher average daily gain, average daily feed intake and feed efficiency (P<0.001) than CON group. At 64 days of age, BW was higher in CFC group compared with CON group (P<0.001). Blood samples were collected at days 31, 38, 45 and 52 of age. From days 31 to 52 significant differences in the somatotropic axis between groups were observed. In particular, growth hormone levels were higher only at the end of the 1st week of dietary treatment (P<0.05) in CFC group animals compared with CON group animals. The IGF-I trend was similar between groups even if the IGF-I levels were higher in the CFC group than CON group 1 week after starting treatment (P<0.01). The IGF-binding protein 3 (IGFBP-3) levels were higher in the first 2 weeks of dietary treatment and lower in the 3rd week in CON group compared with CFC group (P<0.01). Specifically, the IGFBP-3 profile was consistent with that of IGF-I in CFC group but not in CON group. At the same time, an increase of leptin in CFC compared with CON group was observed (P<0.05). Piglets fed the CFC diet showed a lower diarrhoea incidence (P<0.05) and a lower number of antibiotic interventions (P<0.05) than CON diet from 31 to 51 days of age. Pig-major acute-phase protein plasma level (P<0.01) and interleukin-6 gene expression (P<0.05) were higher in CON group than CFC group at the end of 1st week of dietary treatment. In conclusion, this study showed that CFC diet influences the hormones related to energy balance enhancing the welfare and growth of piglets. Furthermore, the increase in feed intake during 3 weeks of dietary treatment improved the feed efficiency over the entire post-weaning period.

Monitoring blood plasma leptin and lactogenic hormones in pregnant sows.

The mechanism of action of leptin in pregnant breeding sows, in which hyperphagia is managed through dietary strategies, is yet to be clarified. The aim of this study was to monitor leptin concentrations and their interactions with lactogenic hormones in Large White×Landrace breeding multiparous sows (n=15). All sows showed a normal body condition (mean body condition score: 2.96). Blood samples were collected the day after weaning the litters, at insemination, every 15 days up to day 45 of pregnancy and every 7 days from day 46 to farrowing. At delivery, the placenta was collected for the analysis of leptin and leptin receptor expressions. Plasma leptin levels increased from the end of mid gestation (day 72) and remained high until farrowing (P<0.05). As expected, plasma prolactin (PRL), low during most of pregnancy, increased during the 2 weeks before farrowing (P<0.05), whereas progesterone levels reached plateau at 30 days of gestation and decreased at farrowing (P<0.05). Cortisol levels peaked close to farrowing (P<0.05). Leptin was expressed in the placenta, where the receptor expression analysis showed the presence of the short form but not of the long form. A positive correlation was found between leptin and PRL concentrations during mid (r=0.430; P<0.001) and late (r=0.687; P<0.001) pregnancy, and with progesterone in early pregnancy (r=0.462; P<0.05). During late gestation, a positive correlation was observed between leptin and cortisol (r=0.585; P<0.001). Our results suggested that, in restrictively fed pregnant sows, the leptin levels increased from the end of mid pregnancy to delivery, confirming the presence of leptin resistance. We showed a correlation between leptin and lactogenic hormones during different stages of pregnancy in sows. Lactogenic hormones show pregnancy-specific changes in their secretion and all may become involved in modulating leptin signal.

Effects of dietary nucleotide supplementation on growth performance and hormonal and immune responses of piglets.

The effects of dietary nucleotide supplementation from 9 days of age until the end of post-weaning on piglets hormonal and immune responses and on growth performance were investigated. During lactation (days 9 to 21) and post-weaning (days 22 to 55) 10 [HBI Fomeva11 × (Large White × Landrace)] litters (n = 108 piglets) had ad libitum access to two standard diets, both supplemented with 0% (T0 group) or 0.1% (T1 group) of yeast extract nucleotides. BW of piglets at days 21 (P < 0.10), 35 and 55 (P < 0.05) was greater in T1 compared with T0. Feed intake was not different between groups (P > 0.05). Cortisol content was lower in T1 than in T0 at days 28 and 35 (P < 0.05), whereas growth hormone was lower at day 35 (P < 0.05). Levels of IGF-1 were similar across groups (P > 0.05). Nucleotide-supplemented diets increased lymphocyte subpopulation CD4-CD8+high at days 21 and 35 (P < 0.05), whereas CD4+CD8- cells were higher in T1 than in T0 at day 21 (P < 0.05). Peripheral blood mononuclear cells cytokine expression was influenced by dietary nucleotide supplementation. At weaning, interleukin (IL)-6 and IL-1ß expression was lower (P < 0.05) in T1 compared with T0, whereas the expression of interferon (IFN)-γ and IL-10 was higher (P < 0.05). At day 28, piglets in T1 showed higher values of tumor necrosis factor (TNF)-α expression than T0 and lower values of IL-10 expression (P < 0.05). Dietary nucleotide supplementation had a suppressive effect on IL-6 and IL-10 expression (P < 0.05) at day 35. On the contrary, the expression of IFN-γ, TNF-α and IL-1ß was enhanced (P < 0.05). In conclusion, these results suggest that starting a dietary nucleotide supplementation before weaning can improve the adaptive capabilities of weaned piglets to the stressors, enhancing the growth performance.

Peripheral cytokine expression in Standardbred mares at different adiposity during the periparturient period.

The aim of this study was to evaluate whether the peripheral cytokine expression could be affected by differences in fat thickness in healthy mares during the periparturient period (last weeks of pregnancy and first weeks of lactation). At the beginning of the 11th month of gestation, 18 mares with normal body condition score (BCS; 5) were divided into two groups with low (L; ≤12 mm; n = 12) and high (H; >12 mm; n = 6) fat thickness. Blood samples were collected every 10 days from the 11th month of gestation to 20 days post partum. Peripheral blood mononuclear cells were separated and tumour necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1α (IL-1α), -1ß (ILß), -2 (IL-2) and -6 (IL-6) gene expressions were performed by using reverse transcriptase PCR. TNF-α and IFN-γ expressions were affected by fatness group, as the sampling period influenced the expression of all cytokines with the exception of IFN-γ. The interaction between fatness group and sampling period tended to be significant (P < 0.10) only for IL-1ß, TNF-α and IL-2. In H group, compared with L group, IL-1ß and IL-2 significantly (P < 0.05) increased at parturition. TNF-α peripheral expression increased from parturition to reach the peak at +10 days (P < 0.05) only in H group. In conclusion, in normal BCS periparturient mares, small body fat thickness variations influence the peripheral cytokine expression, showing a possible role for cytokines in parturition and lactation, events strongly linked to adipose tissue availability.

Relationship between body fat and body condition score and their effects on estrous cycles of the Standardbred maiden mare.

Standardbred maiden mares are generally stressed and in poor physical condition because of their incorrect management at the end of their racing careers. The purpose of this study was to identify an objective assessment that, similar to body condition score (BCS) determination, is easy to measure and able to confirm or improve fattening status assessment, as well as to ascertain whether a relationship with reproduction efficiency exists in subjects destined for a first-time insemination program. The authors assessed 29 Standardbred maiden mares (7 +/- 2 years old) during the breeding season. On January 15 (day 0), the same operator performed the following on all subjects: the first gynecological and ultrasound examination, a BCS assessment (range 0 to 5), and an adiposity objective assessment (i.e., measurement of fat thickness by ultrasound scan). At day 0, all mares were in seasonal anestrous. On ovulation day, all subjects exited the study. Both techniques were shown to be significantly and reciprocally correlated (r = 0.976; P < 0.01) to the first seasonal ovulation in maiden mares (-0.772 and -0.805, respectively, for fat thickness and BCS; P < 0.01). Based on the results obtained, regression equations for the prediction of days to the first seasonal ovulation (y) were created. The best predictive equation was the following: y = 26.714x(3) - 202.44x(2) + 446.04x - 195.65 (R(2) = 0.783; SE = 17 d; P0.01), with an independent BCS variable. In conclusion, this study suggests that increasing the plane of nutrition (i.e., flushing), starting approximately 3 weeks before the breeding season, stimulates ovarian activity in stressed maiden mares.

Relationships between backfat depth and plasma leptin during lactation and sow reproductive performance after weaning.

The aim of this study was to determine relationships between sow backfat depth, plasma leptin concentrations, and reproductive performance after weaning. On the day of farrowing (day 0), and at weaning (day 21), single blood samples were obtained from 120 mixed-parity sows and their backfat depth (P2) measured. Based on backfat depth at day 0, sows were classified as FAT (>24 mm, n = 16), MEDIUM (16-24 mm, n = 54), or THIN (<16 mm, n = 14). Sows were further classified on the basis of P2 backfat changes during lactation of <2 mm, 2-4 mm, or >4 mm. Reproductive performance was measured as weaning-to-oestrous intervals (WOI) of <6 d, 6-9 days, or > or =10 d, and pregnancy rates. There was a positive relationship (P < 0.0001) between backfat depth at day 0 and backfat loss during lactation. The WOI was not associated with backfat depth at day 0 or 21 (P > 0.1 for both). Pregnancy rate was not associated with backfat depth at day 0 (P > 0.1) but pregnant sows had a greater backfat depth at weaning (16.5 +/- 0.3 and 14.9 +/- 0.6 mm, P < 0.04). Backfat loss during lactation was positively associated with WOI (P < 0.01) and negatively associated with pregnancy rate (P < 0.04). Plasma leptin concentrations were higher (P < 0.001) in FAT sows than in MEDIUM or THIN sows on both days but there was no relationship between plasma leptin concentrations and reproductive performances after weaning. It is concluded that plasma leptin is associated with backfat depth and that loss of backfat depth during lactation is associated with reproductive performance. However, there is no direct association between plasma leptin and reproductive performance.