Salmonella is the most common cause of foodborne illnesses worldwide. Poultry eggs are a major contamination source of Salmonella. The prevalence of Salmonella has been effectively reduced since a series of measures were taken to reduce contamination in egg-laying houses. In the present study, 1,512 environmental samples obtained from layer farms of different production scales were screened in a voluntary Salmonella survey study. Contaminations were detected using a PCR method. Genetic relationships among Salmonella samples were specified using molecular typing by enterobacterial repetitive intergenic consensus (ERIC)-PCR. The survey results showed that two layer farms, located in the Shandong and Hebei provinces, were contaminated with Salmonella. Thirty-one samples from these two farms, including feed, drinking nipples, egg collection belt, air inlets and outlets, air, overshoes, and eggshells, were identified as Salmonella-positive. It was observed that certain samples within the henhouses as well as in the egg collecting areas showed relatively high genetic similarities. The survey conclusively revealed minor Salmonella contamination in northern China. Moreover, various areas within the layer farms were identified as part of the propagation chain of Salmonella. Furthermore, evidence of cross-contamination of Salmonella was found in the laying houses and egg collection areas, even between these two regions. Therefore, it is necessary to establish routine Salmonella detection and subsequent environmental control measures in order to decrease the prevalence of Salmonella.
Many types of Bacillus thuringiensis (Bt)-crops are being grown worldwide, triggering concerns about their potential impact on humans and livestock. To ensure better yield and food safety in China, an attempt has been made to develop Bt-rice targeting a broad range of insects. We aimed to investigate whether feeding genetically modified rice expressing the Bt chimeric Cry1Ac/Cry1Ab protein has any effects on the intestinal microbiota of broilers. Broilers were fed either Bt-rice or its unmodified isogenic parent line for 42 days, and total DNA was isolated from cecum contents for high-throughput sequencing of the 16S rRNA gene. In total, 1,241,005 reads, assigned to 12 phyla, 31 families, and 48 genera were generated. No significant differences were observed in the relative abundance of organisms identified among the major phyla, families, and genera, except for two less abundant families, Thermoanaerobacteraceae and Peptostreptococcaceae, and two less abundant genera, Anaerotruncus and Gelria. The results were in agreement with those from culture-based analysis and Biolog EcoPlates. These results illustrate that feeding Bt-rice has no adverse effects on the broiler intestinal microbiota and provide sufficient support for the food safety of Bt-rice.
The aim of this study was to investigate the effects of olive leaf and marigold extracts on the apparent total tract digestibility (ATTD) of the principal nutrients and energy, as well as on mineral utilization (Ca, P, Mg, Mn, Fe, Cu and Zn) in relation to bone characteristics in broilers fed walnut- or linseed oil-supplemented diets. Thirty-six 12-day-old commercial broilers Ross 308 were reared in metabolic cages, assigned to one of the six dietary treatments (3 × 2 factorial design): three supplements (not supplemented, olive leaf extract, or marigold extract), and two oils (walnut or linseed oil). The results showed that the marigold extract reduced Zn and P balances and tended to lower the balance of ash and Mg, and the ATTD of Zn and Mg. Diets with linseed oil increased the ATTD of acid detergent fiber and reduced the ATTD of the organic residue and Cu. No differences in the bone characteristics of tibia were observed between treatments. These results indicated that the inclusion of marigold extract had a negative effect on the Zn and P balance, and that neither extract had any major effect on the digestion and utilization of energy and other investigated nutrients, or on bone mineralization, irrespective of the oil source included in the diet.
We conducted two trials to evaluate the methionine-sparing effects of choline (Chol) and betaine (Bet), and their effects on growth performance and blood antioxidative potential in heat-stressed broiler chickens fed methionine (Met)-deficient diets. We used 360 1-day-old broiler chicks (Ross 308) in a completely randomized study with 5 replicate pens of 12 birds each. After Day 21, we raised the temperature to 35±3°C using an automated air-forced heater for 12 hours/day from 8 am to 8 pm to expose the birds to heat stress. In Trial 1, the treatments comprised a negative control (control-; 1200 mg/kg Met-deficient), a positive control (control+; recommended level of Met), 280Chol (control- plus 280 mg/kg Chol), 560Chol (control- plus 560 mg/kg Chol), 320Bet (control- plus 320 mg/kg Bet), and 640Bet (control- plus 640 mg/kg Bet); and in Trial 2, the treatments comprised a negative control (control-), a positive control (control+), 140Chol+160Bet (control- plus 140 mg/kg Chol and 160 mg/kg Bet), 280Chol+160Bet (controlplus 280 mg/kg Chol and 160 mg/kg Bet), 140Chol+320Bet (control- plus 140 mg/kg Chol and 320 mg/kg Bet), and 280Chol+320Bet (control- plus 280 mg/kg Chol and 320 mg/kg Bet). Compared with the other treatments, the feed conversion ratio (FCR) was improved in the 280Chol and control+ groups in Trials 1 and 2 (P<0.05). In Trial 2, the cost of meat production for the entire experimental period (1–42 days) was higher in the 140Cho+320Bet-fed birds than in the other birds (P<0.05), except the control- birds. Supplementing diets with 280 mg/kg of Chol significantly reduced the serum concentration of uric acid compared with the control+ group (P<0.05). Our results indicate that the Met requirements of heat-stressed broiler chickens can be reduced by 20% (1200 mg/kg) if the diet is supplemented with 280 mg/kg of Chol.
This study was conducted to evaluate the effect of Saccharomyces cerevisiae yeast cell walls (YCWs) in diets with low doses of aflatoxin B1 (AFB1) and ochratoxin A (OTA), alone or in combination, on broiler performance and immune response. A total of 210 male broilers aged 1–21 days were used. Broilers were completely randomized into seven treatments with five replicates of six broilers each, as follows: 1) control diet; 2) control + 350 µg/kg AFB1; 3) Control + 350 µg/kg OTA; 4) Control + 350 µg/kg AFB1 and 350 µg/kg OTA; 5) Control + 350 µg/kg AFB1 and 1.5 kg/ton YCW; 6) control + 350 µg/kg OTA and 1.5 kg/ton YCW; 7) control + 350 µg/kg AFB1, 350 µg/kg OTA, and 1.5 kg/ton YCW. The broilers were housed under environmentally controlled conditions in Petersime battery cages. Weight gain, feed intake, and feed conversion index were measured. The relative weights of the thymus, spleen, and bursa of Fabricius (BF) were evaluated. The local immune response was assessed by quantifying the level of intestinal immunoglobulin A (IgA). The cellular immune response was evaluated using a delayed hypersensitivity test. Hemograms and blood cell counts were also performed. The results showed that mycotoxins decreased performance and reduced the immune response (p<0.05) of broilers. Weight gain and feed conversion improved in the groups receiving YCWs. The YCWs increased (p<0.05) intestinal IgAs and the cellular immune response (p<0.05). The addition of YCWs also affected the relative weight of the thymus, spleen, and BF (p<0.05), and the leukocyte, lymphocyte, and heterophil counts (p<0.05). The addition of YCWs can be an alternative to counterage the negative effect of low doses of AFB1 and OTA in broilers diets.
This study was designed to investigate the effects of dietary fenugreek seed extract (FSE) supplementation on egg production, egg quality, blood profiles, cecal microflora, and excreta noxious gas emission in laying hens. A total of 384 laying hens (26-weeks old, Hyline-brown) were fed three different levels of FSE (0, 0.05, and 0.1%) in a cornsoybean diet for 6 weeks. The inclusion of FSE in the laying hen diet did not affect egg production, feed intake, or feed conversion among treatments; however, egg weight, eggshell breaking strength, eggshell thickness, and yolk color increased in FSE-fed groups (linear, P<0.05). Supplemental FSE decreased the serum total cholesterol concentration, whereas the HDL-cholesterol concentration increased in the FSE fed-groups (linear, P<0.05). FSE led to an increase in cecal Lactobacillus number (linear, P<0.05), and a decrease in Escherichia coli number (quadratic, P<0.05) and excreta ammonia gas emission (linear, P<0.05). These results suggest that the addition of FSE does not increase egg production, but may affect egg quality, serum total- and HDL-cholesterol concentration, and cecal microflora. FSE also decreased ammonia gas emission in laying hen excreta.
The study was conducted to determine the chemical composition and nutritive value of sorghum dried distillers grains with solubles (sDDGS) and its effect as a feed supplement on the performance of geese. Experiment 1 showed that the gross energy, crude protein, ether extract, crude fiber, calcium, phosphorus, and amino acid content values of sDDGS were 17.87 MJ/kg and 15.48, 4.26, 31.46, 0.17, 0.25, and 0.06–3.18% [dry matter basis (DM)], respectively. Experiment 2 used fasting–force feeding to measure the true metabolizable energy of sDDGS (11.38 MJ/kg DM) and true total tract digestibility of amino acids (43.16–80.92% DM) in geese. Experiment 3 examined the effectiveness of sDDGS as a feed supplement for geese. Three hundred and fifteen 35-day-old male Sichuan white geese with an initial average bodyweight of 1,732 g were randomly allocated to five treatments. Geese in each treatment group were fed one of five experimental diets (control diet alone, or supplemented with 4, 8, 12, or 16% sDDGS) until 70 days of age. Inclusion of sDDGS in the diet did not affect daily average weight gain (P>0.05). Birds fed diets containing up to 8% sDDGS had higher average feed intake (P<0.05) than geese fed the control diet, and the feed/gain ratio in geese fed diets containing 16% sDDGS was higher (P<0.05) than in the control and the 4% sDDGS group. The yields of breast meat, leg meat, subcutaneous fat and skin, and abdominal fat were not affected (P>0.05) bydietary sDDGS levels. Generally, sDDGS is a potentially valuable feedstuff for geese, but it should be supplemented with a high-energy or protein-rich ingredient. To improve growth performance and carcass yield, up to 12% sDDGS can be included in diets from 35 to 70 days of age.
Guanidinoacetic acid (GAA) has been shown to spare arginine (ARG) requirements in chickens. ARG plays a critical role in enhancing growth and preventing right ventricular hypertrophy (RVH) in broiler chickens subjected to hypobaric hypoxia. However, ARG is not available as a feed grade supplement in the market. Therefore, we evaluated the effects of commercially available GAA supplement as an alternative on growth performance and RVH in broilers raised at high altitude (2100 m). Five graded levels of GAA ranging from 0 (control) to 2 g/kg were provided in isoenergetic and isonitrogenous diets to broilers (Ross 308) from day 1 to 42, post-hatch. Results indicated that responses to GAA were nonlinear and attained plateau values within the studied range of GAA supply. While weight gain and feed intake were unaffected by GAA supply, feed conversion ratio was improved by GAA supplementation up to 1.5 g/kg. Similar trends were observed for the proportions in the liver and heart, as well as hematocrit. GAA supplementation at 1 and 1.5 g/kg resulted in reduced abdominal fat deposition as well as a decline in right-tototal ventricular weight ratio (RV:TV, an index of RVH). A significant (P<0.05) increase in serum nitric oxide concentration was observed at 1 and 1.5 g/kg GAA supplementation. However, GAA supply led to lower serum malondialdehyde and uric acid levels than in the control. In conclusion, GAA supplementation up to 1.5 g/kg had the potential to improve growth performance and RVH response. Meanwhile, GAA supply beyond 1.5 g/kg could deteriorate these responses.
Gross, histological, and immunohistochemical changes in the combs of chickens after bile duct ligation (BDL) are described. Gross reductions in comb size and volume and lower serum testosterone levels were evident in chickens after BDL. Histologically, atrophic combs were characterized by reduced blood capillary diameter, decreased acid mucopolysaccharides, thinning of the stratum germinativum of the epidermis and dermis, and reduced immunostaining intensity of androgen receptors. These results suggest that the affected cells in atrophic combs are androgen targets. BDL caused testicular atrophy in chickens, a primary complication of liver disease, and the resultant low serum testosterone levels subsequently caused atrophy of the comb. In other words, the atrophy of the comb observed in BDL chickens was a secondary complication of liver dysfunction that simulated the effects of liver disease.
Microcystins (MCs) are included in drinking water and a family of cyclic heptapeptide hepatotoxins that have been implicated in the impairment of liver function in various animals. There is scarce information on the effect of MCs on cytokines and apoptotic gene expression and on whether MCs can induce inflammation and apoptosis in avian hepatic tissue. This study investigated the expression of genes related to proinflammatory interleukins, apoptosis, and antioxidant function in chicken liver tissues cultured in the presence of different doses of microcystin-leucine-arginine (MC-LR). Livers were collected from five hens and liver slices were placed in sterile tubes containing Dulbecco's medium supplemented with 0, 1, 10, or 100 ng/mL of MC-LR. After 6 h of cultivation, total RNA was extracted and quantitative PCR analysis was performed for interleukin genes (IL-1β, IL-6, and IL-8), TNF sf15, an apoptotic gene (caspase-3), and genes involved in antioxidant function ([catalase [CAT ], glutathione peroxidase [GSH-PX ], and superoxide dismutase [SOD]). Liver tissues in each group were fixed for histopathology. MC-LR downregulated the mRNA levels of IL-1β, IL-8, and TNF sf15 as compared to the control (0 ng/mL) in dose-dependent patterns; however, the differences were not significant. The expression of IL-6 in liver tissues exposed to 100 ng/mL of MC-LR was significantly (P<0.05) lower than that in tissues exposed to 1 ng/mL. In contrast, MC-LR upregulated the mRNA expression of caspase-3 and genes involved in antioxidant function in the liver tissues after 6 h, without the difference reaching statistical significance. Hepatocytes showed vacuolar degeneration and focal necrosis according to the dose of MC-LR. This study highlighted the risk of low doses of MC-LR in chicken liver. Moreover, MC-LR could modulate the transcriptional patterns of at least IL-6 in liver-tissue culture of chicken after 6 h of exposure.