Rectal microbiomes and serum metabolomics reveal the improved effect of Artemisia ordosica crude polysaccharides on the lactation performance, antioxidant status, and immune responses of lactating donkeys.

This study is aimed at investigating the effects of dietary supplementation with Artemisia ordosica crude polysaccharides (AOCP) on lactation performance, antioxidant status, and immune status of lactating donkeys and analyzing rectal microbiomes and serum metabolomes. Fourteen lactating Dezhou donkeys with similar age (6.16 ± 0.67 yr of BW ± SD), weight (250.06 ± 25.18 kg), DIM (39.11 ± 7.42 d), and average parity of 3 were randomly allocated into 2 treatments: a control group (CON, basal diet) and an AOCP group (AOCP, basal diet with 1.0 g/kg DM AOCP). Ten weeks were allotted for the experiment, 2 wk for adaptation, and 8 wk for collecting data and samples. The results showed that supplementation of donkey diets with AOCP increased lactation performance, including DMI, milking yield, estimated milk yield, solids-corrected milk, ECM, milk fat yield, milk protein yield, milk lactose yield, milk TS yield, and milk SNF yield. The digestibility of DM, CP, ADF, and NDF was increased in the AOCP group compared with the CON group. The AOCP group increased the concentrations of IgA, IgG, and IgM, the activities of the superoxide dismutase, catalase, and total antioxidant capacity in the serum. Artemisia ordosica crude polysaccharides decreased the concentrations of tumor necrosis factor-α, nitric oxide, reactive oxygen species, and malondialdehyde in the serum. Compared with the CON group, AOCP increased propionate, butyrate, isovalerate, and total VFA concentrations in rectal feces (P < 0.05). The addition of AOCP to increased diversity (Shannon index) and altered structure of the rectal microflora. As a result of AOCP supplementation, there has been a significant improvement in the colonization of beneficial bacteria, including Lactobacillus, Unclassified_f_Prevotellacea, Ruminococcus, and Fibrobacter genera. In contrast, a decrease in the colonization of the Clostridium_sensu_stricto_1 bacterial genus and other pathogenic bacteria was observed. Meanwhile, metabolomics analysis found that AOCP supplementation upregulated metabolites l-tyrosine content while downregulating 9(S)-HODE, choline, sucrose, lysophosphatidylcholine (LysoPC) (18:0), LysoPC (18:1(9Z)), and LysoPC (20:2(11Z,14Z)) concentrations. These altered metabolites were involved in the PPAR signaling pathway, prolactin signaling pathway, glycerophospholipid metabolism, carbohydrate digestion and absorption, and tyrosine metabolism pathways, which were mainly related to antioxidant capacity, immune responses, and protein metabolism in the lactating donkeys. As a consequence of feeding AOCP diets, beneficial bacteria were abundant, and antioxidant and protein metabolism-related pathways were enriched, which may enhance lactation performance in donkeys. Therefore, supplementing AOCP diets is a desirable dietary strategy to improve donkey health and lactation performance.

Effects of corn particle size on growth performance, gastrointestinal development, carcass indices and intestinal microbiota of broilers.

This experiment was conducted to investigate the effects of different corn particle sizes on growth performance, gastrointestinal development, carcass processing yields and intestinal microbiota of caged broilers. One-day-old Ross 308 broilers were randomly divided into 8 treatments with 10 replicates per treatment and 30 birds per replicate pen. The experiment lasted 37 d. Feed and water were provided ad libitum. The results showed as follows: birds fed diets with the FG corn between d 1 and 13 and CG corn between d14 to 37 had increased body weight, daily gain, and feed intake (P < 0.05). Birds fed diets with CG corn between d 24 to 37 had a heavier relative weight of gizzard at d 38 (P < 0.05). Birds fed diets with FG corn from d 1 to 13 and the CG corn from d 14 to 37 had a higher carcass yield and a relative thigh weight at d 38 (P < 0.05). The intestinal microbiota was significantly affected by different corn particle sizes. The relative abundance of Lactobacillaceae was significantly decreased, whereas that of Peptostreptococcaceae was increased (P < 0.05) in birds fed with the CG corn between d1 to 37. The relative abundance of Acinetobacter was significantly increased in birds fed the FG corn between d1 to 37 (P < 0.05). In conclusion, the use of FG corn in the starter phase and CG corn in the grower and finisher phases was beneficial to growth performance, gastrointestinal development and intestinal microbial structure of broilers reared in cages.

Effects of rearing system and narasin on growth performance, gastrointestinal development, and gut microbiota of broilers.

This study was conducted to evaluate the effects of 3 rearing systems (FL: flooring litter rearing, MC: multilayer cage rearing, PN: plastic net rearing) with or without supplemental narasin on growth performance, gastrointestine development and health of broilers. A total of 2,400 one-day-old Ross 308 mixed-sex broilers (1:1 ratio of males and females) were used in a completely randomized design utilizing a 3 × 2 factorial arrangement of treatments, with 12 replicates per treatment. Each replicate for FL, MC, and PN consisted of 34 birds per floor pen, 30 birds per cage, and 36 birds per net pen, respectively, ensuring the same stocking density (12 birds/m2) across the 3 systems. Results showed that lower ADG (average daily gain), ADFI (average daily feed intake), and FCR (feed conversation ratio) observed in the MC group than those of the other 2 systems from 1 to 36 d of age (P < 0.05). Narasin inclusion in the diets decreased ADFI and FCR significantly (P < 0.05). Multilayer cage and PN rearing systems reduced the relative weight of the gizzard significantly (P < 0.05). Compared with FL, MC reduced the relative weight of the duodenum, jejunum, and ileum (P < 0.05). The mRNA expression levels of the ileal IL-1ß and IFN-γ in FL were higher than those in PN and MC (P < 0.05). Narasin decreased the ileal mRNA expression of TNF-α (P < 0.05). Different rearing systems changed the ileal microflora structure of broilers. The FL system increased the ileal microbial diversity of broilers and the relative abundance of Actinobacteria. Narasin combined with MC increased the relative abundance of Proteobacteria. In conclusion, birds reared in PN had a higher body weight. The MC birds had poorer intestinal development and health condition, higher abundance of Proteobacteria, but better FCR. The FL rearing appeared to be propitious for gastrointestinal development and health. Narasin inclusion in the diets improved FCR and changed the relative abundance Proteobacteria of broilers.

[Progress of researches on the development of non-benzimidazoles for the treatment of echinococcosis].

The long-term use of benzimidazoles for the treatment of echinococcosis may cause multiple adverse reactions and low compliance. A search for novel agents, as an alternative of benzimidazoles, is therefore of great significance for the treatment of echinococcosis. This review focuses on the progress of researches on non-benzimidazoles for the clinical treatment of echinococcosis, including anti-parasitic agents, anti-proliferative agents and plant extracts, so as to provide insights into the further development of non-benzimidazoles.

Genistein improves the reproductive performance and bone status of breeder hens during the late egg-laying period.

Genistein (GEN), a type of soy isoflavones, is similar to estrogen structurally and functionally. The effects of dietary gen on the reproductive performance and bone status of breeder hens were investigated. A total pf 720 laying broiler breeder (LBB) hens were randomly allocated into 3 groups with supplemental dietary GEN doses (0, 40, 400 mg/kg). Each treatment has 8 replicates of 30 birds. The results indicated that supplemental GEN significantly improved the egg production and eggshell strength of LBB hens. Dietary GEN was deposited into the egg yolk, which decreased malonaldehyde in the follicle and egg yolk. The levels of vitellogenin (VTG), progesterone, and follicle-stimulating hormone in the serum of GEN-treated groups were elevated compared with the control group. Furthermore, GEN treatment downregulated the mRNA expression of insulin-like growth factor binding protein in the fallopian tube, whereas 40 mg/kg GEN treatment upregulated estrogen receptor α expression. Both the mRNA expression of VTG-II in the liver and mRNA expression of amphiregulin in the fallopian tube were upregulated after 40 and 400 mg/kg GEN treatment. In the 400 mg/kg GEN-treated group, the levels of calcitonin and alkaline phosphatase in the serum were increased compared with the control group, which was consistent with the increased levels of calcium and phosphorus in the tibia. Supplemental GEN (400 mg/kg) improved the tibia strength of LBB hens, whereas 40 mg/kg GEN had better effects on laying performance. In summary, dietary GEN could improve the egg production and quality, as well as the bone status of LBB hens during the late egg-laying period.

High stocking density alters bone-related calcium and phosphorus metabolism by changing intestinal absorption in broiler chickens.

Live performance, bone health and metabolic responses to the interaction among stocking density and dietary concentrations of total calcium (TCa) and non-phytate phosphorus (NPP) were determined on 2,232 Ross 308 female broilers over a 3-wk experimental period. From 22 d of age, birds were randomly divided into 48 groups and provided with different corn-soybean meal-based diets varying in TCa (0.70% or 0.90%) and NPP (0.28% or 0.36%) content at 1 of 2 stocking densities [28.6 (LSD, 13 broilers/m2) and 39.6 (HSD, 18 broilers/m2) kg of predicted final BW/m2 floor space], according to a 2 × 2 × 2 factorial design with 6 replications in each treatment. Regardless of NPP supplementation, a high-TCa (0.90%) diet aggravated the impact of HSD on growth (BW gain and feed efficiency, P < 0.001) and motility (gait score, P < 0.001). This might be explained by deteriorating tibia quality (relative weight, mineral composition and biomechanical property; P < 0.01), due to the involvement of decreasing duodenal absorption (type IIb sodium-phosphate co-transporter mRNA, P < 0.001) in reduced phosphorus retention (P < 0.001). On the contrary, increasing dietary NPP (0.36%), particularly if high in TCa (0.90%), boosted TCa retention (P < 0.05) by improving absorption (calcium-binding protein D28k transcription, P < 0.05) for LSD chickens, hence enhancing bone development (relative tibia weight and tibia breaking strength, P < 0.05) and leg health (walking ability, P < 0.05). Together, HSD and LSD birds show an impaired TCa tolerance and a higher TCa+NPP threshold, respectively, to allow the optimization of bone quality via altered intestinal absorption.

Glucose and lipid metabolism disorders in the chickens with dexamethasone-induced oxidative stress.

The purpose of this study was to investigate the effects of long-term treatment with dexamethasone (DEX) on the antioxidation and nutrition metabolism in broiler chickens. Broilers were placed on a high-nutrient diet for 41 days, and half were given orally DEX-supplemented water at 20 mg/L every other day from 19 to 41 days of age. DEX treatment downregulated superoxide dismutase activity as well as the mRNA expression of CuZn-superoxide dismutase and glutathione peroxidase with a decrease in GSH/GSSG ratio and an increase in malondialdehyde level in the liver of broilers. DEX treatment aggravated oxidative damage in the liver and, therefore, increased the sensitivity of broilers to ascites syndrome with higher mortality and reduced growth performance. Serum metabolomics analysis showed that DEX treatment significantly increased the levels of glucose, intermediates in protein metabolism (valine, proline, serine, threonine and urea) and lipid metabolism-related products (palmitic acid, stearic acid and cholesterol) while decreasing the levels of ß-hydroxy butyric acid, succinic acid and malic acid, demonstrating that DEX treatment inhibited the Krebs cycle and the oxidation of fatty acids, and promoted the de novo synthesis of fatty acids as well as protein decomposition in the liver of broilers. Additionally, detection of metabolism-related enzymes revealed that DEX treatment inhibited glycolysis and promoted glycogen decomposition. In summary, DEX treatment resulted in oxidative stress and glucose and lipid metabolism disorders in the broilers.

High dietary biotin levels affect the footpad and hock health of broiler chickens reared at different stocking densities and litter conditions.

Responses to stocking density (SD), dietary biotin concentration and litter condition were evaluated on 2016 Ross 308 male broilers in the fattening period (day 22-day 42). The birds were placed in 48 pens with either dry or wet litter to simulate the final stocking density of 30 kg (12 broilers/m2 ; normal stocking density, NSD) and 40 kg (16 broilers/m2 ; high stocking density, HSD) of body weight (BW)/m2 floor space. A corn-soybean meal-based diet was supplemented with biotin to provide a normal (NB; 155 µg/kg) or high (HB, 1521 µg/kg) level of dietary biotin. There were six repetitions per treatment. The inappropriate moisture content of litter associated with HSD was avoided (p < 0.05) by good management (SD difference: dry litter, 6.65% vs. wet litter, 13.23%; 42 days), which made it advantageous (p < 0.01) for footpad (SD difference: dry litter, 0.118 vs. wet litter, 0.312; weekly average value) and hock health (SD difference: dry litter, 0.090 vs. wet litter, 0.303; weekly average value) of HSD birds, but not (p > 0.05) for growth and processing yield. In HSD, the biotin effect (gains, FCR) was significantly higher (p < 0.01) than in NSD. The similar response of HSD birds to supplemental biotin was observed (p < 0.05) for lesion scores of footpad and hock in particularly finishing chickens, and a significant interaction (p < 0.01) among stocking density, biotin supplementation and litter condition existed from 35 to 42 days of age. Taken together, increasing dietary biotin improves the performance and well-being of broiler chickens stocked at high densities in litter-independent and litter-dependent manners respectively.

Choline requirements of male White Pekin ducks from 21 to 42 d of age.

1. A dose-response experiment with 6 dietary choline concentrations (0, 342, 779, 1285, 1662 and 1962 mg/kg) was conducted with male White Pekin ducks to estimate the choline requirement from 21 to 42 d of age. 2. Ninety 21-d-old male White Pekin ducks were allotted to 6 dietary treatments, each containing 5 replicate pens with three birds per pen. At 42 d of age, final weight, weight gain, feed intake and feed/gain were measured. Liver was collected to determine total liver lipid, triglyceride and phospholipids. 3. Significant positive effects of dietary choline on final weight, weight gain and feed intake were observed. In addition, dietary choline supplementation significantly decreased liver lipid and triglyceride content and increased liver phospholipids of Pekin ducks. 4. According to broken-line regression analysis, the choline requirements of male White Pekin ducks from 21 to 42 d of age for weight gain, feed intake and total liver lipid were 980, 950 and 1130 mg/kg. Pekin ducks needed more choline to prevent excess liver lipid deposition than to maintain growth.

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.

Long-term effects of choline on productive performance and egg quality of brown-egg laying hens.

A total of five hundred forty 19-wk-old HyLine Brown hens were used to study the long-term effects of increasing choline with 0 (control), 425, 850, 1,700, 3,400, and 6,800 mg/kg of corn-soybean meal-based diets on productive performance and egg quality. Phase 1 was from 19 to 58 wk, and phase 2 was from 59 to 68 wk. During the whole experimental period, dietary choline had no significant effects on feed intake, egg weight, and egg mass (P > 0.05). During phase 1, egg production decreased linearly (P < 0.05) and feed conversion ratio (FCR) tended to increase linearly (P = 0.057) with increasing choline level in the diet. Moreover, BW decreased both linearly (P < 0.01) and quadratically (P < 0.05) as choline increased from 0 to 6,800 mg/kg. No significant treatment effects were found for shell thickness and shell strength of eggs (P > 0.05). However, albumen height and Haugh units increased linearly (P < 0.01 and P < 0.05, respectively) as choline increased during phase 2. Compared with the control group, diets supplemented with 425 or 850 mg of choline/kg significantly (P < 0.01) improved yolk color during phase 1. This study indicates that a dietary choline level of no more than 700 mg/kg is sufficient to maintain egg production. The effect of choline on egg quality was minimal when hens were fed a corn-soybean meal-based diet from 19 to 68 wk of age.

Effects of Dietary L-carnitine Supplementation on Growth Performance, Organ Weight, Biochemical Parameters and Ascites Susceptibility in Broilers Reared Under Low-temperature Environment.

The objective of this study was to investigate the effects of L-carnitine on growth performance, organ weight, biochemical parameters of blood, heart and liver, and ascites susceptibility of broilers at different ages reared under a low-temperature environment. A total of 420 1-d-old male Ross 308 broilers were randomly assigned to two dietary treatments with fifteen replicates of fourteen broilers each. Treatment diets consisted of L-carnitine supplementation at levels of 0 and 100 mg/kg. At 11-d of age, low temperature stress was used to increase ascites susceptibility. Blood, heart and liver samples were collected at different ages for analysis of boichemical parameters. The results showed that, there was no significant difference in growth performance with L-carnitine supplementation, but the mortality due to ascites was significantly decreased. Dietary L-carnitine supplementation significantly reduced heart index (HI) and ascites heart index (AHI) on d 21, lung index (LUI) on d 35 and liver index (LI) on d 42. The broilers fed diets containing L-carnitine had significantly lower red blood cell counts (RBC), hemoglobin (HGB) concentration and hematocrit (HCT) on d 42. Dietary L-carnitine supplementation significantly reduced malondialdehyde (MDA) content of heart tissue on d 21 and 35, and significantly increased total superoxide dismutase (T-SOD) and Glutathione peroxidase (GSH-Px) activity of the heart on d 21 and 42. L-carnitine supplementation significantly reduced serum triglyceride (TG) content on d 28 and 35 and serum glucose (GLU) on d 35 and 42, and significantly increased serum total protein (TP) and globulin (GLO) content on d 42. L-carnitine supplementation significantly enhanced liver succinodehydrogenase (SDH), malic dehydrogenase (MDH) and Na(+)-K(+)-ATPase activity on d 28, and tended to reduce the lactic acid (LD) level of liver on d 35 (p = 0.06). L-carnitine supplementation significantly reduced serum uric acid (UA) content on d 28, 35 and 42. Based on the current results, it can be concluded that dietary L-carnitine supplementation reduced organ index, red blood cell counts and hematocrit, enhanced antioxidative capacity of the heart, enhanced liver enzymes activity involved in tricarboxylic acid cycle, and reduced serum glucose and triglyceride. Therefore, it is suggested that L-carnitine can potentially reduce susceptibility and mortality due to ascites.

Conjugated linoleic acids alleviate infectious bursal disease virus-induced immunosuppression in broiler chickens.

The immunoregulatory actions of conjugated linoleic acid (CLA) of relevance to viral disease pathogenesis and immune responses were investigated. To test the hypothesis that CLA ameliorates immunosuppression, we developed a viral challenge model by infecting chickens with infectious bursal disease virus (IBDV). After 14 d of dietary supplementation with either soybean oil or CLA, half of the chickens in each group were challenged with IBDV. We examined the effect of CLA on the development of lesions (i.e., lymphoid depletion and necrosis) and observed the immune responses against IBDV. The IBDV infection depleted lymphocytes in the medullary area and significantly stimulated interferon (IFN)-γ and IL-6 mRNA relative expression of bursa (P < 0.05) compared with the uninfected bursa. Compared with the CLA diet, lymphocytes depletion was more accentuated in chickens fed the control diet, whereas IFN-γ and IL-6 mRNA relative expression were upregulated (P < 0.05). Additionally, histopathological examination of the bursa revealed that the pathological changes tended to be more severe in infected chickens fed the control diet, which also significantly decreased (P < 0.05) on lymphocyte proliferation. Significant interactions were found between infection and diets for lymphocyte proliferation, antibody titers, and IFN-γ mRNA relative expression (P < 0.05). The results of this study indicate that dietary CLA enhanced immune function in chickens, particularly those of the IBDV-immunosuppressive status. Furthermore, at the molecular level, the immunoregulatory functions of CLA on chickens are attributable mainly to the antiinflammatory properties of CLA and are mediated, at least in part, through suppressing IBDV-specific proinflammatory cytokines mRNA relative expression.

Sodium alginate oligosaccharides from brown algae inhibit Salmonella Enteritidis colonization in broiler chickens.

The effects of sodium alginate oligosaccharides (sAO) on growth performance, cecal microbiota, Salmonella translocation to internal organs, and mucosal immune responses to challenge with Salmonella enterica serovar Enteritidis in broiler chickens were investigated. We designed an experiment with a 2 × 3 factorial arrangement, in which 3 feed treatments with supplementation of sAO at 0 (controls), 0.04, or 0.2% were provided in the diet for birds not challenged or challenged with Salmonella Enteritidis. There were 5 randomly placed replicate pens for each treatment. At 8 to 12 d of age, one-half the poults were orally gavaged with 10(8) cfu of Salmonella Enteritidis and the nonchallenged groups were inoculated with sterile PBS. Body weight loss and mortality resulting from Salmonella infection were mitigated by the addition of sAO. Supplementation of sAO at 0.2% was the most effective concentration for reducing Salmonella colonization and increasing the number of lactic acid bacteria in the cecum of chickens challenged with Salmonella Enteritidis. Cecal Salmonella Enteritidis-specific IgA production was significantly increased by sAO at 0.2% at 5 d postchallenge compared with the other treatments and was maintained at higher levels at the 2 dosages of sAO at 10 d postchallenge. With Salmonella Enteritidis challenge, sAO at 0.04% showed an anti-inflammatory effect through upregulation of interleukin (IL)-10 expression in the cecal tonsils. The supplementation level of 0.2% showed dramatic immunostimulatory activity by inducing interferon-γ, IL-10, and IL-1ß mRNA expression in cecal tonsils of nonchallenged birds. However, the high level of sAO induced a robust mucosal immune response in the absence of a challenge, and this may have led to a decline in BW. These findings suggest that dietary sAO can decrease Salmonella colonization and improve intestinal barrier function and performance of chickens.

Influence of organic zinc supplementation on the antioxidant status and immune responses of broilers challenged with Eimeria tenella.

An experiment was conducted to investigate the influence of Zn supplementation on the performance, antioxidant status, and immune responses of broilers challenged with Eimeria tenella. A total of 384 male broilers (1 d old) were assigned to 8 treatments consisting of 8 replicates of 6 chicks each. A basal corn-soybean meal diet (29.6 mg of Zn/kg) was supplemented with methionine hydroxyl analog-Zn chelate at 0, 20, 40, and 60 mg/kg of diet. At 21 d of age, birds were orally gavaged with 1.5 × 10(4) sporulated E. tenella oocysts. Dietary Zn supplementation had no effect on growth performance of either the challenged or nonchallenged birds. Activities of Cu-Zn superoxide dismutase and glutathione peroxidase were increased (P < 0.001) with increasing Zn levels in both the challenged and nonchallenged groups. Lipid peroxidation tended to be reduced (P = 0.08) at Zn inclusion of 20 and 40 mg/kg. In vitro lymphocyte proliferation responses to mitogen concanavalin A and LPS were not influenced by dietary Zn or challenge. The main effects of Zn level and challenge were significant for secretory IgA on d 28 (P < 0.01) and 35 (P < 0.001). During both periods, secretory IgA of birds receiving dietary Zn supplementation was higher (P < 0.05) than that of those receiving no Zn supplementation. Birds fed Zn supplementation excreted fewer oocysts in the excreta than those receiving no Zn supplement (P < 0.001). Results indicated that organic Zn supplementation reduced oxidative stress and improved some immune responses irrespective of whether birds were healthy or challenged with E. tenella.

Effects of liquid DL-2-hydroxy-4-methylthio butanoic acid on growth performance and immune responses in broiler chickens.

An experiment was conducted to determine the effects of different doses of liquid dl-2-hydroxy-4-methylthio butanoic acid (LMA) on growth performance and immune response in broiler chickens. In an arrangement with 4 graded levels of LMA to meet 80, 100, 120, and 140% of methionine requirements of broilers recommended by Chinese feeding standards for chickens, 256 one-day-old Arbor Acres male broiler chickens were randomly divided into 4 treatments with 8 replicates of 8 birds each. Growth performance, cellular immunity, and humoral immunity were determined. Results from increasing LMA levels were as follows. There were no significant differences (P > 0.05) in body weight gain and feed intake among the treatments, but the ratio of feed to gain was linearly decreased and significantly greatest (P < 0.05) in the group fed at 80% of methionine requirement. Serum globulin levels on d 21 and 42 were linearly increased significantly (P < 0.05); phagocytosis of neutral red of peripheral blood lymphocyte was quadratic and was lowest in the deficient group (P < 0.05). The proliferation of peripheral blood lymphocytes in response to lipopolysaccharide was quadratically influenced, and that of the 120% group on d 21 and the 100% group on d 42 was significantly greater than in the other groups (P < 0.05). Antibody titers to Newcastle disease virus on d 4 after the first inoculation of the vaccine were quadratically increased, anti-bovine serum albumin antibody production on d 13 after the second immunization was quadratic, and antibody titers were greatest in the groups fed at 100 or 120% of methionine requirement. In conclusion, methionine deficiency resulted in decreased feed utilization and decreased humoral and nonspecific immuno-competence of broiler chickens. The use of LMA to correct a methionine deficiency corrected these problems.

Dietary conjugated linoleic acid improves antioxidant capacity in broiler chicks.

1. The influence of dietary conjugated linoleic acid (CLA) on the antioxidant status in the absence or presence of endotoxin exposure was studied with male broiler chicks. 2. In experiment 1, a total of 240 1-d-old broilers were allotted into 4 dietary groups (0, 2.5, 5.0 or 10.0 g pure CLA/kg) to study the influence of CLA on growth performance and antioxidant defence systems. The results showed that growth performance was not altered by 42 d of CLA consumption. Increased total superoxide dismutase (TSOD) activities in liver, serum and muscle were observed in chicks given 10.0 g CLA/kg diet. Dietary CLA at 10.0 g/kg also markedly elevated liver catalase (CAT) activity. Malondialdehyde (MDA), a marker of lipid peroxidation, decreased in liver, serum and muscle in chicks given 5.0 and 10.0 g CLA/kg diet. 3. In experiment 2, a total of 120 1-d-old broilers were fed on a control diet (without CLA) or 10.0 g CLA/kg diet. Half of the birds fed on each diet were injected intraperitoneally with 0.25 mg/kg body weight of Salmonella enteritidis lipopolysaccharide (LPS) at 16, 18 and 20 d of age. Decreased glutathione peroxidase (GSH-Px), TSOD activity and increased ceruloplasmin and MDA concentrations were seen in the challenged chicks. Dietary CLA prevented the loss of body weight gain and feed conversion ratio of chicks followed repeated endotoxin exposure. CLA partially inhibited the increase of serum ceruloplasmin and MDA at 17 and 21 d of age and notably suppressed the decrease of serum TSOD activity at 21 d of age. 4. These results suggested that dietary CLA enhances the activity of antioxidant enzymes including TSOD and CAT. Supplementation of CLA has been shown to ameliorate the antioxidant balance and performance of chicks during oxidative stress.

Effect of magnesium on reactive oxygen species production in the thigh muscles of broiler chickens.

1. The objective of the present study was to investigate the effect of magnesium (Mg) on reactive oxygen species (ROS) production in the thigh muscles of broiler chickens. A total of 96 1-d-old male Arbor Acre broiler chickens were randomly allocated into two groups, fed either on low-Mg or control diets containing about 1.2 g/kg or 2.4 g Mg/kg dry matter. 2. The low-Mg diet significantly increased malondialdehyde (MDA) concentration and decreased glutathione (GSH) in the thigh muscles of broiler chickens. ROS production in the thigh muscle homogenate was significantly higher in the low-Mg group than in the control group. Compared with the control, muscle Mg concentration of broiler chickens from the low-Mg group decreased by 9.5%. 3. Complex II and III activities of the mitochondrial electron transport chain in broilers on low-Mg diet increased by 23 and 35%, respectively. Significant negative correlations between ROS production and the activities of mitochondrial electron transport chain (ETC) complexes were observed. 4. The low-Mg diet did not influence contents of iron (Fe) or calcium (Ca) in the thigh muscles of broiler chickens and did not influence unsaturated fatty acid composition (except C18:2) in the thigh muscles. 5. A low-Mg diet decreased Mg concentration in the thigh muscles of broiler chickens and then induced higher activities of mitochondrial ETC, consequently increasing ROS production. These results suggest that Mg modulates the oxidation-anti-oxidation system of the thigh muscles at least partly through affecting ROS production.

Effects of dietary coenzyme Q10 supplementation on hepatic mitochondrial function and the activities of respiratory chain-related enzymes in ascitic broiler chickens.

1. One hundred and sixty 1-d-old Arbor Acre male broiler chicks were fed with maize-soybean based diets for 6 weeks in a 2 x 2 factorial experiment. The factors were CoQ10 supplementation (0 or 40 mg/kg) and Escherichia coli lipopolysaccharide (LPS) challenge (LPS or saline). 2. CoQ10 was supplemented from d 1. From d 18, the chickens received three weekly i.p. injections of LPS (1.0 mg/kg BW) or an equivalent amount of sterile saline as control. From d 10 on, all chickens were exposed to low ambient temperature (12 to 15 degrees C) to induce ascites. 3. The blood packed cell volume and ascites heart index of broiler chickens were reduced by dietary CoQ10 supplementation. Mitochondrial State 3 and State 4 respiration, respiratory control ratio and phosphate oxygen ratio were not changed, but H+/site stoichiometry of complex II + III was elevated by dietary CoQ10 supplementation. 4. Cytochrome c oxidase and H+-ATPase activity were increased by CoQ10 supplementation, whereas NADH cytochrome c reductase and succinate cytochrome c reductase were not influenced. Mitochondrial anti-ROS capability was increased and malondialdehyde content was decreased by CoQ10 supplementation. 5. The work suggested that dietary CoQ10 supplementation could reduce broiler chickens' susceptibility to ascites, which might be the result of improving hepatic mitochondrial function, some respiratory chain-related enzymes activities and mitochondrial antioxidative capability.

Reduction of ascites mortality in broilers by coenzyme Q10.

Effects of coenzyme Q10 (CoQ10) supplementation on growth performance and ascites were studied in broilers. One hundred eighty 1-d-old Arbor Acre male broiler chicks were randomly allocated into 3 groups with 6 replicates each. From d 8, the diets were supplemented with CoQ10 at levels of 0, 20, and 40 mg/kg, respectively. From d 15 to 21, all the chicks were exposed to low ambient temperature (15 to 18 degrees C) to induce ascites. Average feed intake, BW gain, and feed conversion ratio of the broilers during 0 to 3 wk, 3 to 6 wk, and 0 to 6 wk were measured. The results showed that there were no influences observed on broilers' growth performance, but the mortality due to ascites was reduced by CoQ10 supplementation (P < or = 0.05). Erythrocyte osmotic fragility (EOF) was significantly decreased by 40 mg/kg CoQ10 compared with the control, but no significant changes were observed on blood packed cell volume (PCV) among the treatments. Pulmonary arterial diastolic pressure was significantly decreased on d 36, but no significant changes were observed on right ventricular pressure (RVP), pulmonary arterial systolic pressure, and the maximum change ratio of right intraventricular pressure (+/- dp/ dtmax). Ascites heart index (AHI) was significantly decreased by 40 mg/kg CoQ10 supplementation (P < or = 0.05). The results of this study suggested that CoQ10 has a beneficial effect in reducing ascites mortality in broilers, and 40 mg/kg CoQ10 seems to be more effective than 20 mg/ kg CoQ10.