The effect of tributyrin supplementation to milk replacer on plasma glucagon‐like peptide 2 concentrations in pre‐weaning calves

The objective of this study was to evaluate the effect of tributyrin (TB) supplementation to milk replacer (MR) on performance, health, and blood concentrations of metabolite and glucagon‐like peptide (GLP‐2) in pre‐weaning calves. Twenty Holstein heifer calves were raised on an intensified nursing program using MR supplemented with either palm oil (CON) or TB (TB) at 0.3% (as fed basis) for 7 weeks starting 1 week after birth. Calves were fed a calf starter and kleingrass from the beginning of the study. Blood samples were obtained weekly to measure blood glucose, serum β‐hydroxybutyric acid (BHBA), insulin‐like growth factor 1 (IGF‐1), and plasma GLP‐2 concentrations. Starter DMI and metabolizable energy (ME) intake were lower in TB calves at 46, 47, from 49 to 55 days after birth compared with the CON calves. However, any growth parameters were not affected by TB treatment. Blood glucose, serum BHBA, and IGF‐1 concentrations were not affected by TB supplementation. On the other hand, mean plasma GLP‐2 concentration among whole experimental period was higher for TB (0.60 ng/ml) compared with CON (0.41 ng/ml). In conclusion, feeding MR supplemented with TB increases plasma GLP‐2 concentration, which might counterbalance the growth performance of TB calves despite the decreased ME intake.     

Insulin‐independent actions of glucagon‐like peptide‐1 in wethers

Insulin‐independent actions of glucagon‐like peptide‐1 (GLP‐1) are not yet clear in ruminants. Four Suffolk mature wethers (60.0 ± 6.7 kg body weight (BW)) were intravenously infused with insulin (0.5 mU/kg BW/min; from 0 to 90 min) and GLP‐1 (0.5 μg/kg BW/min; from 60 to 150 min) with both hormones co‐administered from 60 to 90 min, in a repeated‐measure design under euglycemic clamp for 150 min, to investigate whether GLP‐1 has insulin‐independent actions. Jugular blood samples were taken at 15‐min intervals for plasma hormones and metabolites analysis. Compared to baseline concentrations (at 0 min), insulin infusion decreased (P < 0.05) plasma concentrations of glucagon, non‐esterified fatty acids (NEFA), lactate, nonessential amino acids (NEAA), branched‐chain amino acids (BCAA), total amino acids (TAA) and urea nitrogen (UN). Insulin plus GLP‐1 infusion induced a greater increase (P < 0.05) in plasma concentrations of insulin and triglyceride (TG), but decreased (P < 0.05) glucagon, total cholesterol (T‐Cho), NEAA and UN plasma concentrations. GLP‐1 infusion increased (P < 0.05) NEFA, β‐hydroxybutyrate and TG, but decreased (P < 0.05) glucagon, T‐Cho, NEAA, BCAA and UN plasma concentrations. In conclusion, GLP‐1 exerts extrapancreatic roles in ruminants not only insulin‐independent but probably, in contrast to non‐ruminants, antagonistic to insulin effects.     

Influences of protein ingestion on glucagon‐like peptide (GLP)‐1‐immunoreactive endocrine cells in the chicken ileum

Influences of a specific dietary nutrient on glucagon‐like peptide (GLP)‐1‐containing cells in the chicken intestine are not yet clear. Significance of dietary protein level on GLP‐1‐containing cells in the chicken ileum was investigated. Chickens fed control or experimental diets of varying protein levels were examined using immunohistochemical and morphometrical techniques. We show that the protein ingestion had an impact on the activities of GLP‐1‐immunoreactive cells in the chicken ileum. Weight gains declined with decreasing dietary crude protein (CP) levels, but no significant differences were detected in the daily feed intake and villous height. GLP‐1‐immunoreactive cells with a round or oval shape were frequently observed in the lower CP level groups (4.5% and 0%). Frequencies of occurrence of GLP‐1‐immunoreactive cells were 41.1 ± 4.1, 38.5 ± 4, 34.8 ± 3.1 and 34.3 ± 3.7 (cells/mm², mean ± SD) for dietary CP level of 18%, 9%, 4.5% and 0% groups, respectively and significant differences were recognized between the control and lower CP level groups (P < 0.05). Multiple regression analysis indicated a significant correlation between the daily protein intake and frequencies of occurrence of GLP‐1‐immunoreactive cells. The protein ingestion is one of the signals that influence GLP‐1‐containing cells in the chicken small intestine.     

Effects of glucagon‐like peptides 1 and 2 and epidermal growth factor on the epithelial barrier of the rumen of adult sheep

Epidermal growth factor (EGF) and glucagon‐like peptides (GLP) modulate the tight junctions (TJ) of the intestinal epithelial barrier (EB) of monogastric animals. This work tried to elucidate whether GLP‐1, GLP‐2 and EGF can affect the EB of the rumen. Ovine ruminal epithelia were incubated in Ussing chambers for 7 hr with 25 or 250 nM of either GLP‐1 or GLP‐2 on the serosal side, with 2.5 nM of EGF on the serosal side or with 0.25 or 2.5 nM EGF on the mucosal side. No treatment affected tissue conductance. Short‐circuit current (I_sc) was affected by time and treatment and their interactions. Only 250 nM of either GLP‐1 or GLP‐2 decreased I_sc in certain periods compared with 25 nM GLP‐1 or 0.25 nM mucosally applied EGF; however, not when compared to control epithelia. Fluorescein flux rates (J_fluor) of ruminal epithelia were affected by treatment, time and time × treatment interaction. The time × treatment interaction was based on an increase in J_fluor between the first and last hour in epithelia incubated with 25 nM GLP‐1 or GLP‐2 and in epithelia incubated with EGF. After 7 hr incubation, claudin‐7 mRNA expression was downregulated in all treatments. Claudin‐1 mRNA was upregulated after incubation with 2.5 nM EGF on the serosal side, claudin‐4 mRNA was downregulated by 2.5 nM EGF on the mucosal side, and occludin mRNA was increased after incubation with 250 nM GLP‐2. The protein abundance of all tested TJ proteins was not influenced by treatment. We conclude that GLP‐1, GLP‐2, and EGF have no obvious acute effects on the EB of ruminal epithelia under simulated physiological conditions ex vivo. However, by decreasing the mRNA expression of claudin‐7 and partly affecting other TJ proteins, they may modulate EB in the longer term or under certain conditions.     

Growth of rumen papillae in weaned calves is associated with lower expression of insulin‐like growth factor‐binding proteins 2, 3, and 6

This study aimed to characterize the relationship between the growth of rumen papillae in calves and the mRNA expression of insulin‐like growth factor‐binding proteins (IGFBPs) in the rumen papillae. The length of rumen papillae, the mRNA expression of IGFBPs in rumen papillae by quantitative real‐time PCR, and the presence of insulin‐like growth factors I and II (IGF‐I and II) by immunohistochemistry (IHC) were analyzed in nine Holstein calves divided into three groups: suckling (2 weeks, n = 3), milk‐continued (8 weeks, n = 3), and weaned (8 weeks, n = 3). The length of rumen papillae was greater (p < 0.01) in weaned calves than in suckling and milk‐continued calves, whereas the expressions of IGFBP2, IGFBP3, and IGFBP6 genes were lower (p < 0.05) in the rumen papillae of weaned calves than in milk‐continued calves. Thus, rumen papillae length and IGFBP2, 3, and 6 expressions were negatively correlated. The IHC analysis showed that IGF‐I and IGF‐II were present in the rumen epithelium of calves. These results suggested that the growth of rumen papillae after weaning is associated with the induction of IGFs by the low levels of IGFBP2, IGFBP3, and IGFBP6.     

Ruminal epithelial insulin‐like growth factor‐binding proteins 2, 3, and 6 are associated with epithelial cell proliferation

The aim of this study was to identify factors that regulate ruminal epithelial insulin‐like growth factor‐binding protein (IGFBP) expression and determine its role in rumen epithelial cell proliferation. Primary bovine rumen epithelial cells (BREC) were incubated with short‐chain fatty acids (SCFAs) at pH 7.4 or 5.6, lactate, lipopolysaccharide (LPS), insulin‐like growth factor‐I (IGF‐I), ‐II (IGF‐II), or recombinant bovine IGFBP2 (rbIGFBP2). The mRNA expression levels of IGFBP in BREC were analyzed using quantitative real‐time polymerase chain reaction (qRT‐PCR). The proliferation rate of BREC was analyzed using a WST‐1 assay. IGFBP2 gene expression tended to be lower with SCFA treatment (p < .1), and IGFBP6 gene expression was significantly lower with SCFA treatment (p < .05). IGFBP3 and IGFBP6 gene expression tended to be higher with d ‐Lactate treatment (p < .1). IGFBP3 gene expression was significantly higher (p < .05) with LPS treatment. BREC treated with IGF‐I grew more rapidly than vehicle control‐treated cells (p < .01); however, recombinant bovine rbIGFBP2 inhibited IGF‐I‐induced proliferation. IGF‐II and/or rbIGFBP2 did not affect BREC proliferation. Taken together, SCFA treatment decreased IGFBP2 and IGFBP6 expression in rumen epithelial cells, and lower expression of these IGFBP might promote rumen epithelial cell proliferation by facilitating IGF‐I.     

Oxyntomodulin reduces expression of glucagon‐like peptide 1 receptor in the brainstem of chickens

Oxyntomodulin (OXM) is a peptide released from the gut and attenuates food intake by acting on hypothalamus. However, its role at the molecular level is not well studied. In the first section of this study, we analysed the effect of OXM on food intake behaviour after injecting into the lateral ventricle of chickens. The outcome showed that food intake decreased significantly after administering 4 nmol of OXM. In the second part, the expression of glucagon‐like peptide 1 receptor (GLP‐1R) in the brainstem was analysed by real‐time RT‐PCR. The results showed that expression of GLP‐1R was reduced to 27% and 16% at 30 and 90 mins after injection of OXM respectively. In saline‐injected chickens, no reduction in GLP‐1R was seen. It can be concluded that OXM has a down regulatory effect on the responding receptor, GLP‐1R and OXM in chicks has the same reductive effect on food intake as in the mammals.     

Polymorphism in promoter region of growth hormone receptor is associated with potential production capacity of insulin‐like growth factor‐1 in pre‐pubertal Holstein heifers

Insulin‐like growth factor‐1 (IGF‐1) is one of the important factors for growth, milk production and reproductive functions and mainly released from the liver in response to growth hormone (GH) via GH receptor (GHR) in cattle. Recently, some single nucleotide polymorphisms (SNPs) were identified in the bovine GHR gene. Some GHR‐SNPs were shown to be related to plasma IGF‐1 concentration in cattle. Hence, the capacity to IGF‐1 production in the liver might be affected by GHR‐SNP and associated with performance in the future. This study examined whether GHR‐SNP is associated with IGF‐1 production in the liver of pre‐pubertal heifers. In 71 Holstein calves, blood samples for genomic DNA extraction were obtained immediately after birth. To genotype the GHR‐SNPs in the promoter region, polymerase chain reaction (PCR) products were digested with restriction enzyme NsiI (cutting sites: AA, AG and GG). All heifers at 4 months of age were intramuscularly injected with 0.4 mg oestradiol benzoate. Blood samples were obtained from the jugular vein just before (0 h) and 24 h after injection. The number of AA, AG and GG at the NsiI site was 0, 17 and 54 respectively. In AG and GG, plasma GH concentrations were higher pre‐injection than 24 h post‐injection (p < 0.01). Moreover, plasma GH concentrations in AG post‐injection were higher than in GG (p < 0.05). In contrast, the GG genotype exhibited higher plasma IGF‐1 concentrations in pre‐injection than post‐injection (p < 0.01), although oestradiol did not change IGF‐1 concentration in the AG genotype. We conclude that the GG polymorphism in the promoter region of GHR is associated with a higher potential capacity of IGF‐1 production in the liver of cattle.     

Effect of porcine glucagon‐like peptides‐2 on tight junction in GLP‐2R + IPEC‐J2 cell through the PI3k/Akt/mTOR/p70S6K signalling pathway

Because of rare glucagon‐like peptide‐2 (GLP‐2) receptor (+) cells within the gut mucosa, the molecular mechanisms transducing the diverse actions of GLP‐2 remain largely obscure. This research identified the naturally occurring intestinal cell lines that endogenously express GLP‐2R and determined the molecular mechanisms of the protective effects of GLP‐2‐mediated tight junctions (TJ) in GLP‐2R (+) cell line. (i) Immunohistochemistry results showed that GLP‐2R is localised to the epithelia, laminae propriae and muscle layers of the small and large bowels of newborn piglets. (ii) GLP‐2R expression was apparent in the cytoplasm of endocrine cells in IPEC‐J2 cell lines. (iii) The protein expressions of ZO‐1, claudin‐1, occludin, p‐PI₃K, p‐Akt, p‐mTOR and p‐p70^S6K significantly (p < 0.05) increased in GLP‐2‐treated IPEC‐J2 cells, and all of them significantly (p < 0.05) decreased when LY‐294002 or rapamycin was added. GLP‐2 improves intestinal TJ expression of GLP‐2R (+) cells through the PI₃k/Akt/mTOR/p70^S6K signalling pathway.     

Methyl donors dietary supplementation to gestating sows diet improves the growth rate of offspring and is associating with changes in expression and DNA methylation of insulin‐like growth factor‐1 gene

The study aimed to investigate the effects of maternal dietary methyl donors on the performance of sows and their offspring, and the associated hepatic insulin‐like growth factor‐1 (IGF‐1) expression of the offspring. A total of 24 multiparous sows were randomly fed the control (CON) or the CON diet supplemented with methyl donors (MD) at 3 g/kg betaine, 15 mg/kg folic acid, 400 mg/kg choline and 150 μg/kg VB₁₂, from mating until delivery. After farrowing, sows were fed a common lactation diet through a 28‐days lactation period and six litters per treatment were selected to be fed until at approximately 110 kg BW. Maternal MD supplementation resulted in greater birthweight (p < 0.05) and increased the piglet weights (p < 0.01) and litter weights (p < 0.05) at the age of day 28, compared with that in CON group. The offspring pigs in the MD group had greater ADG (p < 0.05) and tended to lower F:G ratio (p = 0.07) compared with that of CON group from day 28 to 180 of age. The offspring pigs from MD group had greater serum IGF‐1 concentrations and expressions of hepatic IGF‐1 gene and muscular IGF‐1 receptor (IGF‐1r) protein at birth (p < 0.05), and greater hepatic IGF‐1 protein (p = 0.03) and muscular IGF‐1r gene expressions (p < 0.05) at slaughter, than that from the CON group. Moreover, the methylation at the promoter of IGF‐1 gene in the liver of newborn piglets and finishing pigs was greater in the MD group than that of the CON group (p < 0.05). In conclusion, maternal MD supplementation throughout gestation could enhance the birthweight and postnatal growth rate of offspring, associated with an increased expression of the IGF‐1 gene and IGF‐1r, as well as the altered DNA methylation of IGF‐1 gene promotor.     

Influences of incorporating detoxified Jatropha curcas kernel meal in common carp (Cyprinus carpio L.) diet on the expression of growth hormone‐ and insulin‐like growth factor‐1‐encoding genes

Jatropha curcas is a drought‐resistant shrub or small tree widespread all over the tropics and subtropics. The use of J. curcas (L) kernel meal in fish feed is limited owing to the presence of toxic and antinutritional constituents. In this study, it was detoxified using heat treatment and organic solvent extraction method. The detoxification process was carried out for 60 min to obtain the detoxified meal. Cyprinus carpio L. fingerlings (n = 180; avg. wt. 3.2 ± 0.07 g) were randomly distributed in five treatment groups with four replicates and fed isonitrogenous diets (crude protein 38%) for 8 weeks. The inclusion levels of the detoxified Jatropha kernel meal (DJKM) and soybean meal (SBM) were as follows: control diet was prepared with fish meal (FM) and wheat meal, without any DJKM and SBM; diets S₅₀ and J₅₀: 50% of FM protein replaced by SBM and DJKM respectively; diets S₇₅ and J₇₅: 75% of FM protein replaced by SBM and DJKM respectively. Highest body mass gain and insulin‐like growth factor‐1 (IGF‐1) gene expression in brain, liver and muscle were observed for the control group, which were statistically similar to those for J₅₀ group and significantly (p < 0.05) higher than for all other groups, whereas growth hormone gene expression in brain, liver and muscle exhibited opposite trend. Insulin‐like growth factor‐1 concentration in plasma did not differ significantly among the five groups. Conclusively, growth performance was in parallel with IGF‐1 gene expression and exhibited negative trend with GH gene expression.     

Effect of genistein on IGF‐1 and IGFBP‐1 in young and aged female rat ovary

The objective of this study was to assess the effects of genistein (GEN) on expression of insulin‐like growth factor 1 (IGF‐1) and insulin‐like growth factor binding protein 1 (IGFBP‐1) in young and aged rat ovary. Forty young female Sprague Dawley (SD) rats (200 ± 20 g) and forty aged female SD rats (490 ± 20 g) were selected and according to weight, they were divided into the following five groups with eight animals in each: negative control group (NC), low‐dose group (L), middle‐dose group (M), high‐dose group (H) and positive control group (PC). GEN group received GEN of 15, 30, 60 mg/kg respectively. It lasted 30 days. Concentrations of serum hormones, IGF‐1 and IGFBP‐1 were determined by enzyme‐linked immunosorbent assay (ELISA). Gene and protein expressions of IGF‐1 and IGFBP‐1 were determined by real‐time PCR and Western blot respectively. Compared with NC, GEN significantly increased oestradiol‐17β(E₂) level in aged rat, reduced luteinizing hormone (LH) level in young and aged rat. Serum levels of IGFBP‐1 in young rats were significantly higher in GEN groups (p < 0.05). mRNA and protein expression levels of IGF‐1 and IGFBP‐1 were positively correlated with GEN dose. GEN could significantly reduce the ratio of IGF‐1/IGFBP‐1 of aged rats. Multivariate Cox regression analysis result showed IGF‐1 and IGFBP‐1 levels significantly correlated with GEN dose. We speculate that there is an association between the addition of GEN and expression of IGF‐1 and IGFBP‐1, and the relationship between them is different in young and aged rat.     

Oral administration of synthetic porcine beta‐defensin‐2 improves growth performance and cecal microbial flora and down‐regulates the expression of intestinal toll‐like receptor‐4 and inflammatory cytokines in weaned piglets challenged with enterotoxigenic Escherichia coli

Synthetic porcine beta‐defensin‐2 (pBD‐2) was tested as an alternative to antimicrobial growth‐promoters in pig production. Thirty 21‐day weaned piglets were challenged with enterotoxigenic Escherichia coli, and orally dosed with either sterile water (CON), pBD‐2 (BD) or neomycin sulphate (NS) twice daily for 21 days. pBD‐2 and NS led to higher growth performance, jejunum villus height and increased expression of insulin‐like growth factor‐I compared with the CON group (P < 0.05). Hemolytic E. coli scores from rectal swabs, and copy numbers of E. coli, Bacteroides fragilis and Streptococcus in the cecal digesta of the BD‐ or NS‐treated piglets were lower than those in the CON group (P < 0.05). Messenger RNA levels of toll‐like receptor 4, tumor necrosis factor‐α, interleukin (IL)‐1β, and IL‐8 in the jejunum mucosa of the BD and NS groups were lower than those in the CON group (P < 0.05). Copy numbers of Lactobacilli and Bifidobacteria in the cecal digesta of the BD group were higher than those of the CON and NS groups (P < 0.05). Therefore, pBD‐2 has antimicrobial activity in piglets, and it can improve growth performance, reduce inflammatory cytokine expression and affect intestinal morphological indices in the same way as probiotics. © 2015 Japanese Society of Animal Science     

Effect of dietary methionine on growth performance and insulin‐like growth factor‐I mRNA expression of growing meat rabbits

An experiment was conducted to determine the effects of different amounts of dietary methionine on growth performance, serum protein, growth hormone (GH), insulin‐like growth factor‐I (IGF‐I) concentrations and IGF‐I mRNA expression of growing meat rabbits. One hundred weaned growing meat rabbits were allocated to individual cages and randomly divided into five groups. The methionine addition concentrations of the five groups were 0, 2, 4, 6 and 8 g/kg diet (as‐fed basis) and sulphur amino acids (SAA) concentrations ranging from 3.8 to 11.6 g/kg diet, respectively. The results obtained were as follows: the average daily gain of 2, 4 and 6 g/kg diet groups was higher than that of 0 g/kg diet group (p < 0.01). The feed gain ratio of the 4 g/kg diet group was lower than those of 0 and 8 g/kg diet group (p < 0.01). Methionine concentrations did not affect serum urea nitrogen, total protein, insulin and IGF‐I concentration (p > 0.05). The quadratic effects of methionine on the serum concentration of albumin (Alb) and GH were obtained (p = 0.013, p = 0.018). The quadratic effect of methionine amount on IGF‐I mRNA expression was obtained (p = 0.045). The serum concentration of Alb of the 4 g/kg diet group was higher than those of 0 and 8 g/kg diet group (p < 0.01). The serum concentration of GH of 8 g/kg diet group was higher than that of the 0 g/kg diet group (p < 0.05). The liver IGF‐I mRNA expression of 4 g/kg diet group was higher than those of the 0 and 8 g/kg diet group (p < 0.05). Providing a diet mainly consisted of corn, wheat bran and peanut vine, the optimum dietary methionine addition concentration and SAA concentration for a weaner to 2‐month‐old growing meat rabbits were shown to be 2 and 5.7 g/kg diet respectively.     

Preliminary investigation of blood concentrations of insulin‐like growth factor,insulin, lactate and β‐hydroxybutyrate in dogs with lymphoma as compared with matched controls

It is well established that tumour cells have metabolic differences when compared with normal cells. This is particularly true for energy metabolism in which dogs with cancer have been reported to have higher blood insulin and lactate concentrations than control dogs. Moreover, some human and animal studies suggest that the insulin‐like growth factor 1 (IGF‐1) signalling pathway may play a role in tumorigenesis and tumour progression. At present, IGF‐1 has not been evaluated in dogs with multicentric lymphoma. In this prospective, cross‐sectional study, blood levels of IGF‐1, as well as other markers of energy metabolism—insulin, glucose, lactate, and β‐hydroxybutyrate—were measured in 16 dogs with histologically or cytologically confirmed treatment‐naïve lymphoma. These results were compared with 16 age‐, sex‐ and weight‐matched healthy controls. Dietary histories were collected, and protein, fat and carbohydrate intake were compared between groups. Results demonstrated that IGF‐1, insulin, glucose and insulin:glucose ratio were not different between groups. However, lactate and β‐hydroxybutyrate were higher in the dogs with lymphoma than that in the control dogs (1.74 ± 0.83 mmoL/L vs 1.08 ± 0.27 and 2.59 ± 0.59 mmol/L vs 0.77 ± 0.38 mmol/L, respectively). Median dietary protein, fat and carbohydrates did not differ between the groups. This preliminary study suggests that higher insulin and IGF‐1 levels relative to controls may not be a consistent finding in dogs with lymphoma. The significance of increased β‐hydroxybutyrate in dogs with lymphoma warrants further investigation in a larger prospective study.     

The preliminary study on the effects of growth hormone and insulin‐like growth factor‐I on κ‐casein synthesis in bovine mammary epithelial cells in vitro

The effects of growth hormone (GH) and insulin‐like growth factor‐I (IGF‐I) on protein synthesis and gene expression of κ‐casein in bovine mammary epithelial cell in vitro were studied. The treatments were designed as follows: the growth medium without serum was set as the control group, while the treatments were medium supplemented with GH (100 ng/ml), IGF‐I (100 ng/ml), and GH (100 ng/ml) + IGF‐I (100 ng/ml). The quantity of κ‐casein protein was measured by ELISA, and the κ‐casein gene (CSN3) expression was examined by real‐time quantitative PCR (RT‐qPCR). Compared with the control group, all the experimental groups had greater (p < 0.05) expression of CSN3. The concentration of κ‐casein followed a similar response as CSN3, but the difference between the treatments and the control was not statistically significant (p > 0.05). Furthermore, no synergistic effect of GH and IGF‐I was observed for both the κ‐casein concentration and CSN3 expression. It is therefore concluded that GH or IGF‐I can independently promote the expression of CSN3 in bovine mammary epithelial cells in vitro.     

Short‐term methionine supplementation during the early post‐partum period in primiparous rabbits improves prolificacy associated with an increase in serum concentrations of IGF‐I

The aim of this study was to evaluate the effects of methionine supplementation on energy metabolism and reproductive performance during the early post‐partum period in primiparous does. Forty nulliparous New Zealand White does were used. Females were randomized in two groups at calving: the control group (n = 20) was fed with the basal diet, and the methionine group (n = 20) was fed the basal diet plus 1 g/animal/day of methionine from the day of calving to 4 days post‐partum. Results showed that methionine supplementation increased (p = 0.032) the concentration of insulin‐like growth factor‐1 with respect to control group 4 days post‐partum. It similarly increased the prolificacy (p = 0.03), the number of kits born alive per litter (p = 0.06) and the body gain weight of the litter during supplementation (p = 0.035). These results were observed despite the does in the methionine group having a deeper negative energy balance than the does in the control group. Finally, methionine supplementation did not affect receptivity (p = 0.23), fertility (p = 0.49), the number of kits born dead per litter (p = 0.86) insulin and metabolites as glucose, non‐esterified fatty acids and triglycerides. In conclusion, our results show that methionine supplementation during the first 4 days of the post‐partum period in rabbits increases total litter size and the corporal weight of kits and is associated with an increase in blood concentration of IGF‐1.     

Leptospiral lipopolysaccharide stimulates the expression of toll‐like receptor 2 and cytokines in pig fibroblasts

Pigs throughout the world are afflicted with leptospirosis, causing serious economic losses and potential hazards to human health. Although it has been known that leptospiral lipopolysaccharide (L‐LPS) is involved in an immunological reaction between an antigen and a host cell, little is known about how the immune system of pigs can respond to L‐LPS. Here, we stimulated pig fibroblasts by L‐LPS and then quantitatively measured gene and protein expression levels of two toll‐like receptors (TLRs), TLR2 and TLR4, by real‐time PCR and Western blotting. As a result, expression of TLR2 was found to be significantly up‐regulated within 24 h after L‐LPS stimulation whereas induction of TLR4 expression was relatively weak. We also revealed that of myeloid differentiation primary response gene 88 (MyD88), interleukin 6 (IL‐6) and IL‐8 gene expressions were markedly up‐regulated by L‐LPS stimulation. These results may suggest that the pig cell can activate TLR2 rather than TLR4 by L‐LPS stimulation, thereby inducing expression of cytokines.     

Canine pancreatic islet cell tumours secreting insulin‐like growth factor type 2: a rare entity

Insulin‐like growth factor type II (IGF‐II) is the main cause of non‐islet cell tumour hypoglycaemia (NICTH) and insulin is thought to be the only factor causing hypoglycaemia in insulinomas. However, two case reports of pancreatic neuroendocrine tumours (PNETs) producing IGF‐II have been previously published: a human and a canine patient. In this study, we investigated clinical, histopathological, immunohistochemical and ultrastructural features, and biological behaviour of canine pancreatic IGF‐II‐omas, a subgroup of PNETs that has not been previously characterized. Case records of 58 dogs with confirmed PNETs and hypoglycaemia were reviewed: six patients were affected by IGF‐II‐omas. Surgery was performed in all cases and two dogs had metastases. Four patients remained alive and in remission at 370, 440, 560 and 890 days post‐diagnosis; two died of non‐tumour‐related causes. IGF‐II‐omas can be differentiated from insulinomas through hypoinsulinaemia, IGF‐II positive and insulin negative immunostaining. The prevalence of this neoplasia is low, accounting for just 6% of PNETs.