Longitudinal circulating concentrations of long-chain polyunsaturated fatty acids in the third trimester of pregnancy in gestational diabetes.

AIM: Gestational diabetes mellitus is a common complication of pregnancy. Long-chain polyunsaturated fatty acids (LCPUFA) are essential for fetal neurodevelopment. Docosahexaenoic acid (DHA) is the predominant n-3 LCPUFA in the brain and retina. Circulating absolute concentrations of total n-3 and n-6 LCPUFAs rise during normal pregnancy. It remains unclear whether gestational diabetes may affect the normal rise in circulating concentrations of LCPUFAs in the third trimester of pregnancy - a period of rapid fetal neurodevelopment. This study aimed to address this question. METHODS: In a prospective singleton pregnancy cohort, fatty acids in fasting plasma total lipids were measured at 24-28 and 32-35 weeks of gestation in women with (n = 24) and without gestational diabetes mellitus (n = 116). Fatty acid desaturase activity indices were estimated by relevant product-to-precursor fatty acid ratios. Dietary nutrient intakes were estimated by a food frequency questionnaire. RESULTS: Plasma absolute concentrations of total n-6 LCPUFAs rose significantly between 24-28 and 32-35 weeks of gestation in women with or without gestational diabetes, whereas total n-3 LCPUFAs and DHA concentrations rose significantly only in women without gestational diabetes (all P < 0.01). Delta-5 desaturase indices (20:4n-6/20:3n-6) were similar, but delta-6 desaturase indices (18:3n-6/18:2n-6) were significantly lower in women with gestational diabetes at 32-35 weeks of gestation. Dietary intakes of all fatty acids were comparable. CONCLUSION: The normal rise in circulating absolute concentrations of DHA and total n-3 LCPUFAs in the third trimester of pregnancy may be compromised in gestational diabetes, probably due to impaired synthesis or mobilization rather than dietary intake difference.

Dietary supplementation with sodium bicarbonate improves calcium absorption and eggshell quality of laying hens during peak production.

The advantage of supplemental sodium bicarbonate (NaHCO3) on eggshell quality in laying hens changes with age. Besides increasing calcium (Ca) secretion in the eggshell gland, it may improve Ca absorption in the intestine or kidney. Hy-Line Brown layers (n = 384), 25 weeks of age, were allocated to two treatment groups in two experiments, each of which included 4 replicates of 24 hens. Hens were fed a basal diet (control) or the basal diet containing 3 g NaHCO3 g/kg for 50 or 20 weeks in Experiment 1 or 2, respectively. A 24-h continuous lighting regimen was used to allow hens to consume the dietary supplements during the period of active eggshell formation. In Experiment 1, particularly from 25 to 50 weeks of age, and in Experiment 2, NaHCO3 supplementation favoured hen-d egg production at the expense of lower egg weight. The increased eggshell thickness should have nothing to do with the additional eggshell formation, because of the unchanged egg mass and daily eggshell calcification. At 35 weeks of age in both experiments, NaHCO3 supplementation increased duodenal expression of calbindin-d28k (CaBP-D28k) protein, contributing to higher Ca retention and balance. From 50 to 75 weeks of age in Experiment 1, the hens had little response to NaHCO3 supplementation and showed a negative trend on eggshell thickness and strength. It is concluded that dietary supplementation with 3 g NaHCO3 g/kg improves Ca absorption and eggshell quality of laying hens during the peak but not late production period, with the introduction of continuous lighting.

Influence of dietary nicotinic acid supplementation on lipid metabolism and related gene expression in two distinct broiler breeds of female chickens.

This study aimed to evaluate the influence of supplemental dietary nicotinic acid (NA) on lipid metabolism and hepatic expression of related genes in female chickens of two distinct broiler strains [Arbor Acres (AA) and Beijing-You (BJY)]. The treatments were arranged in a 2 × 4 factorial in a completely randomized design. Day-old females (n = 384) were allocated to four treatments with six cages per treatment and fed diets (basal contained approximately 25 mg NA/kg) supplemented with 0, 30, 60 and 120 mg NA/kg. A sample of 72 birds from each breed was slaughtered and sampled at their different market times (8 week for AA and 16 week for BJY). Arbor Acres broilers had thickness of subcutaneous fat plus the skin (SFS), and plasma concentration of low-density lipoprotein cholesterol (LDLC) and lower percentage of abdominal fat (PAF), plasma concentrations of TG, NEFA and adiponectin than the BJY line. The hepatic transcription of apolipoprotein A-I (ApoA-I), apolipoproteinB (ApoB), and adiponectin was significantly higher in AA broilers than in BJY broilers. In both breeds, BW, PAF, SFS, NEFA and TG were increased with increasing supplementation from 0 to 60 mg NA/kg, but then decreased slightly with 120 mg added NA/kg. With increasing supplementation, hepatic expression and plasma concentrations of adiponectin decreased from 0 to 60 mg added NA/kg and then increased with 120 mg added NA/kg. The expression of ApoA-I and ApoB mRNA showed linear response to dietary supplementation with NA. These findings indicate that: (i) supplementation of NA influenced the lipid metabolism and related gene expression; (ii) when supplemented with 120 mg NA/kg, some pharmacologic actions on lipid metabolism appeared; and (iii) changes in BW and fat deposition appeared to be associated with hepatic expression of adiponectin.

Effect of supplementation of organic manganese on reproductive performance of female Ussuri raccoon dogs (Nyctereutes procyonoides) during the breeding season.

The study was conducted to investigate the effect of dietary manganese (Mn) on reproductive performance of female Ussuri raccoon dogs (Nyctereutes procyonoides) during the breeding season. Healthy female Ussuri raccoon dogs (n=72) were randomly divided into six groups of twelve each. The six experimental diets were formulated to contain graded amounts of Mn (0, 40, 80, 120, 200 and 400mg/kg of diet; Groups A through F, respectively). Litter size of Group D was greater than that of Groups A, B, C and E (P<0.05), with Group E having the smallest litter size. Values of number born alive were affected by different amounts of organic Mn. Number of pups born alive in Group D was greater than that of Groups B, C, E and F (P<0.05). Number of pups weaned alive for Group D was greater than that of Groups A, B, C and E (P<0.05). Mn supplementation of the control diet (containing 24.32 mg/kg from raw materials) with 120 mg/kg of Mn was adequate for female Ussuri raccoon dogs during the breeding season, based on positive effects of reproduction performance.

Increasing dietary vitamin D3 improves the walking ability and welfare status of broiler chickens reared at high stocking densities.

A study was conducted to evaluate the effects of varying dietary vitamin D3 and stocking density on growing performance, carcass characteristics, bone biomechanical properties, and welfare responses in Ross (308) broilers. Experimental diets, containing 1, 10, or 20 times the NRC recommended level of vitamin D3 (200 IU/kg), were formulated with low, medium, or high vitamin D3 levels for 3 growing phases. Two stocking densities were 10 and 16 birds/m(2). One-day-old hatchlings (1,872 males) were randomly assigned to 6 pens in each treatment. Results showed that high stocking density decreased the feed intake, BW gain (P < 0.01), breast muscle yield (P = 0.010), and tibial development (P < 0.01), whereas increasing feed conversion ratio (P < 0.001), and the scores of gait, footpad and hock burn, and abdominal plumage damage (P < 0.01), particularly toward the age when birds attained their market size. Increasing dietary vitamin D3 improved the birds' walking ability and tibial quality (P < 0.05), and reduced the development of footpad or hock dermatitis and abdominal plumage damage (P < 0.01), some aspects of which were age-dependent and appeared to vary with stocking density. These data indicate that increasing supplemental vitamin D3 has a favorable effect on walking ability and welfare status of high stocking density birds, but not on performance.

Effects of dietary vitamin E on immunological stress of layers and their offspring.

In the present study, two experiments were conducted to evaluate the effect of vitamin E (VE) supplementation of a commercial layer diet on the laying performance and immunological stress responses of hens and their offspring. In experiment 1, responses to increased dietary VE levels were evaluated on 180 White Leghorn layers between 20 and 35 weeks of age. There were three levels of VE in the diets (0, 40 and 100 IU/kg) and five replicates per treatment, each containing 12 hens. Results showed that the high level of VE supplementation (100 IU/kg) had a beneficial effect on feed intake and feed efficiency of hens (p < 0.05), compared with the VE-deficient or low-level group. In experiment 2, 540 female progeny from the VE-treated hens in experiment 1 were used. The experimental design consisted of three levels of VE supplementation (the same as their mothers') × 3 vaccinating routines, the first vaccination being administered on day 5, 8 or 11. All vaccines and the subsequent vaccinating intervals were identical. In the interim of the experiment, each bird was injected celiacly with Escherichia coli lipopolysaccharide (LPS). The results showed that antibody titres against Newcastle disease virus (NDV) or avian influenza virus (AIV) and the plasma concentration of interleukin (IL)-1 were increased by the high level of VE supplementation. There were significant effects of the day of initial immunization with infection bursal disease on the NDV and AIV antibody titre, H/L ratio and plasma concentration of corticosterone and IL-1 before and after injecting LPS, suggesting the occurrence of immunological stress. There was also significant interaction between VE and vaccination routine on the immune functions of experimental birds. Considered together with the results of experiment 1, VEs biological function appeared to be dose-dependent, especially with regard to its positive effect on the immune responses of young chickens.

Effect of dietary supplemental nicotinic acid on growth performance, carcass characteristics and meat quality in three genotypes of chicken.

The effects of dietary supplemental nicotinic acid (NA) on growth performance, carcass characteristics and meat quality were investigated in three genotypes of chicken. Fast-growing AA (Arbor Acres) broilers were compared with two genotypes of a slow-growing local breed, Beijing-You, that had undergone selection for and against intramuscular fat content respectively (BJY+IMF and BJY-IMF). The treatments were arranged 3×4 factorial completely randomized design. Day-old females (n=624) were allocated to four treatments with six replicates per treatment and fed diets (basal contained ~25 mg NA/kg) supplemented with 0, 30, 60 and 120 mg NA/kg. A sample of 72 birds from each genotype was slaughtered at market time (8 weeks of age for AA and 16 weeks of age for BJY). The breast muscles of AA broilers were darker, had less redness and yellowness, lower drip loss and higher shear force as compared to the BJY genotypes (p<0.01). The highest drip loss and the lowest shear force among the three genotypes were apparent in BJY+IMF (p<0.01). Increasing supplementation from 0 to 60 mg NA/kg tended to increase average daily gain (ADG), average daily feed intake, width of intermuscular fat band, thickness of subcutaneous fat (including skin) and percentage of abdominal fat but, for most variables, values decreased slightly with 120 mg NA/kg. Increasing supplementation to 60 mg NA/kg decreased (quadratic, p<0.001) drip loss, but it increased at 120 mg NA/kg. The present results indicate that (i) the AA broilers fed corn-soybean meal based-diets require approximately 60 mg NA/kg to maximize ADG and meat product yield and decrease the drip loss of breast muscle; (ii) the addition of 30 mg NA/kg meets the requirement of BJY genotypes; and (iii) there seems to be no beneficial effect of NA supplementation on chicken meat quality except for limiting the drip loss.

Effects of L-arginine supplementation on glucose and nitric oxide (NO) levels and activity of NO synthase in corticosterone-challenged broiler chickens (Gallus gallus).

In the present study, three experiments were conducted to investigate the effect of oral supplementation of l-arginine (ARG) on the disposal of glucose in stressed-broiler chickens (Gallus gallus domesticus). In all the three experiments, the broiler chickens were randomly subjected to one of the four treatments at the beginning of the experiments: oral administration of saline, glucose (2.0g/kg body weight, BW), l-arginine (0.5g/kg BW) or mixed solution (2.0g glucose+0.5g arginine/kg BW). Immediately after the oral treatment, the experimental chickens were subcutaneously injected with corn oil (Experiment 1), corticosterone (CORT, 4mg/kg BW, Experiment 2) or insulin (1U/kg BW, Experiment 3), respectively. Blood samples were obtained at the beginning (0-h), 0.5-, 1- and 2-h time points after injection and the levels of plasma glucose, urate, nitric oxide (NO) and activity of NO synthase (NOS) were measured. The results showed that plasma NO levels and NOS activity were significantly suppressed while glucose and insulin concentrations were increased by CORT treatment. In contrast, insulin administration improved the circulating level of NO and activity of NOS. ARG supplementation could not improve the circulating levels of NO and NOS activity in CORT-challenged chickens and, in turn, the glucose disposal. The result suggests that NO is involved in insulin-mediated glucose transport in chickens, as well as that in mammals. The reduced circulating level of NO resulted from the suppressed activity of NOS rather than the reduced substrate concentration.

Corticosterone administration and dietary glucose supplementation enhance fat accumulation in broiler chickens.

1. The effects of exogenous corticosterone administration and glucose supplementation on energy intake, lipid metabolism and fat deposition of broiler chickens were investigated. 2. A total of 144 three-d-old male chickens were randomly assigned to one of the following 4 treatments for 7 d: a low energy diet (10.9 MJ ME/kg, 200 g/kg CP) with or without corticosterone (30 mg/kg diet) and drinking water supplemented with glucose (80 g/l) or saccharine (2 g/l, control). 3. Body weight (BW) gain and breast and thigh muscle yields (% body mass) were all significantly decreased by corticosterone treatment. The relative cumulative feed intake (RCFI) and relative ME intake (RMEI), rather than the feed (FI) or ME intake (MEI) were increased by corticosterone administration. Both feed efficiency (FE) and caloric efficiency (CE) were decreased by corticosterone administration. Corticosterone administration had no obvious effect on water consumption. 4. Glucose supplementation had no influence on BW gain and breast and thigh muscle yield (as % of body mass). FI or RCFI was decreased while MEI or RMEI was increased by glucose supplementation. FE was improved by glucose treatment, whereas CE was reduced. 5. Liver weight and abdominal, cervical and thigh fat deposits were all significantly increased by either corticosterone or glucose treatment. 6. Plasma concentrations of glucose, urate, triglyceride, non-esterified fatty acids (NEFA), very low density lipoprotein and insulin were all significantly increased by corticosterone treatment. Glucose supplementation had no obvious influence on any of the measured plasma parameters except for NEFA, which were significantly increased. 7. Lipoprotein lipase activities in either cervical or abdominal adipose tissues, rather than in thigh fat tissue, were significantly elevated by either glucose or corticosterone treatment.

Abnormal ACTH and prolactin responses to fenfluramine in rats exposed to single and multiple doses of MDMA.

The present study examined the persistent functional consequences associated with exposure to single and multiple doses of (+/-) 3,4-methylenedioxymethamphetamine (MDMA) as reflected by the neuroendocrine responses to d,l-fenfluramine (FEN). Adult male rats were administered a single dose of MDMA (20 mg/kg, s.c.) and challenged 2 weeks later with saline or FEN (2, 4, 6 and 8 mg/kg, s.c.). The corticotropin (ACTH) response to FEN (6 and 8 mg/kg) was blunted and the prolactin response to FEN (4 and 6 mg/kg) was enhanced in MDMA pre-treated rats. The ACTH and prolactin responses to FEN (6 mg/kg, s.c.) were then evaluated 4, 8 and 12 months after exposure to single and multiple doses MDMA (20 mg/kg, s.c. and 20 mg/kg, s.c., bid, x 4 days, respectively). The ACTH response to FEN was significantly reduced at 4 and 8 months in both MDMA treatment groups, and at 12 months in the multiple dose group only. In contrast, the prolactin response to FEN was enhanced in both groups of MDMA treated rats at 4 months, but only in the multiple dose group at 8 months. By 12 months, the prolactin response to FEN had normalized. Following multiple doses of MDMA, 5-HT concentrations were reduced significantly in the frontal cortex at 4 and 12 months. The results indicate that exposure to single or multiple doses of MDMA can produce functional alterations which can persist for months, whereas the biochemical sequelae were less robust and shorter lived.