Z. Y. Wang

Tagging major quantitative trait loci for sheath blight resistance in a rice variety, Jasmine 85

This study was conducted with a clonal F2 population of rice from a cross between Jasmine 85, a resistant variety, and Lemont, a susceptible cultivar. The rice plants belonging to each F2 clone were divided into two plots, which were put in two replicates, respectively. Clonal parents were tested as controls. The plants were inoculated by short toothpicks incubated with RH-9, a virulent isolate of the pathogenic fungus,Rhizoctonia solani, which causes rice sheath blight. The extreme resistant and susceptible clonal lines were selected for construction of resistant and susceptible DNA pools, respectively. A total of 94 polymorphic markers evenly distributed on 12 rice chromosomes were used for bulked segregant analysis, three positive ones were found polymorphic between the two DNA pools, and three major QTLs for sheath blight resistance, Rh-2, Rh-3 and Rh-7, were identified. The three major QTLs were located on chromosomes 2, 3 and 7, and could explain 14.4%, 26.1% and 22.2% of the phenotypic variation.

Influence of whole corn feeding on the performance, digestive tract development, and nutrient retention of geese

The objective of the current study was to investigate the influence of including whole corn (WC) in goose diets on the performance, digestive tract development, and nutrient retention. A total of 112 Yangzhou geese, 7 d old and with similar BW, were distributed into 8 pens of 14 birds/pen (7 male, 7 female). Each treatment was represented by 4 replicates. Geese were fed corn-soybean-based diets containing 640 g (8-28 d) and 615 g (29-70 d) of corn/kg of diet from 8 to 70 d of age, and 2 particle sizes of corn grains were used: ground corn (GC) and WC. During the period from 8 to 49 d, daily feed intake (P < 0.05) and daily weight gain (P = 0.054) of WC-fed birds tended to be lower than that of GC-fed birds. However, WC diet tended to improve (P = 0.07) G:F from 50 to 70 d of age. Higher relative weights of the gizzard (P < 0.05) at 28, 49, and 70 d, proventriculus at 49 d, and duodenum at 28 and 70 d of age were observed in birds fed the WC diet compared with those fed the GC diet. Intestinal wall thickness in the jejunum and crypt depth and intestinal wall thickness in the ileum were greater (P < 0.05) in WC-fed birds at 28 d of age. Villus height and intestinal wall thickness in the duodenum and villus height in the jejunum were greater in birds fed the WC diet compared with those fed the GC diet at 70 d of age, and birds fed the WC diet had a greater (P < 0.05) intestinal wall thickness, villus height, and crypt depth measurements in the ileum compared with those fed the GC diet. The retention ratio of CP and neutral detergent fiber were higher (P < 0.05) in birds fed the WC diet than in those fed the GC diet. Overall, no negative effect was observed in birds fed the WC diet compared with those maintained on the GC diet.

InDel and SNP Markers and Their Applications in Map-based Cloning of Rice Genes

High-density markers are necessary for map-based cloning of rice genes, but the currently available markers are not satisfactory enough. InDel (insertion-deletion length polymorphism) and SNP (single nucleotide polymorphism) are the new generation of molecular markers and can basically meet the need of fine mapping. InDel and SNP markers can be developed through bioinformatics. These markers are valuable markers with the characters of low cost, high specificity and stability. This article introduced the methods for designing InDel and SNP markers, taking the mapping of a rice rolled leaf gene as an example. In addition, some key factors in improving the design efficiency were also discussed.

Evaluation of Resistance of a Novel Rice Line YSBR1 to Sheath Blight

The novel rice (Oryza sativa L.) line YSBR1 is an intersubspecies hybrid with high level of partial resistance to sheath blight (SB). For the purpose of assessing the resistant level of YSBR1 using multiple approaches, the disease score of YSBR1 was investigated after artificial inoculation in the field and greenhouse in 2006 and 2007. The inhibition rate SB-toxin to the embryo root was also used as a criterion of SB resistance. Compared with other rice genotypes, YSBR1 had significantly higher resistance to SB and the resistance was stable and reliable. The average SB disease score of YSBR1 was 2.39±0.23 and felt in “resistant” grade in the “0–9” rating system when the susceptible control Lemont showed a mean disease score of 7.55±0.26. Correlation analysis showed that the SB-toxin inhibition rate was significantly correlated with disease score from the field test. The SB-toxin inhibition rate of YSBR1 was 57.55%, which was similar to that of Jasmine 85 but significantly lower than that of other tested varieties and Lemont (97.39%). In addition to the high resistance to SB, YSBR1 is also in good performance of plant type and height, growth duration, and grain yield, indicating its prosperous application in variety improvement of SB resistance in rice breeding programs.

Effects of rice husk diluted dietary switching on the phenotypic change of gastrointestinal tract in adult ganders

1. An experiment was conducted to test the directionality, scaling and reversibility of phenotypic responses of the gastrointestinal tract (GIT) of adult ganders to rice husk (RH) diluted dietary switching. 2. A total of 96 140-d-old ganders were acclimatised to a basal diet for 2 weeks. The birds were randomly assigned to 4 treatments. On d 1, diets in the experimental groups were switched from the basal diet to diets which contained 200, 400 or 600 g/kg RH by mass, with no RH in the basal diet. After 21 d, the diet of all the experimental birds was switched back to the basal diet until d 42. 3. Increasing RH content significantly increased feed intake, and a decreased trend appeared after diet-switching. The weights of geese fed on the 600 g/kg RH diet for 21 d reduced, and were significantly less than those of the other three groups, while body weights (BW) of the geese in all groups increased after diet-switching back to the basal diet. At d 21, significantly heavier relative weights of proventriculus, gizzard and all gut components, except duodenum, were observed in birds fed on a 600 g/kg RH diet, and significantly heavier relative weights of gizzard were observed in birds given a 400 g/kg RH diet. Thickness of the two gastric walls, gizzard length and all gut components lengths increased significantly in birds given a 600 g/kg RH diet compared with the other three groups. At d 42, no significant differences were noted in the relative weights or lengths of GIT, except for the caeca, which were significantly heavier in birds fed on 600 g/kg RH diet. 4. The results of the experiment were in accordance with the predictions of the hypothesis that there is matching between loads and capacities. The observed phenotypic responses were directional and scaled to the demands.

Effects of stocking density on growth performance, feather growth, intestinal development, and serum parameters of geese

ABSTRACT This experiment was conducted to evaluate the effects of stocking density on the growth performance, feather growth, intestinal development, and serum parameters of geese. In total, 336 healthy, 28‐day‐old, male Yangzhou goslings were randomly allotted to 30 plastic wire‐floor pens according to 5 stocking densities (2, 3, 4, 5 and 6 birds/m2). The results showed that with the stocking density increased from 2 birds/m2 to 6 birds/m2, the body weights of geese at 42 d (P < 0.001) and 70 d (P < 0.001) were reduced by 10.53% and 10.43% respectively, the primary feather lengths of geese at 42 d (P < 0.001) and 70 d (P = 0.021) were reduced by 20.38% and 6.62% respectively, whereas the feed/gain ratios for 28‐ to 42‐d period and 28‐ to 70‐d period increased from 2.50 to 2.90 (P = 0.001), and 3.80 to 4.24 (P < 0.001), respectively. The relative weights of the jejunum, ileum, and small intestine and the lengths of the jejunum, ileum, and small intestine were all adversely affected (P < 0.05) when stocking density was increased to 6 birds/m2. Serum concentrations of alkaline phosphatase (P = 0.013) and triiodothyronine (P < 0.001) decreased as the stocking density increased. The serum thyroxine concentration of geese from the 6 birds/m2 group was lower than that of geese from the other groups (P < 0.05). The reduction in thyroid hormone concentrations was similar to what was observed in growth rate. All the results suggested that high stocking density will adversely influence thyroid function and the developments of the body weight, body size, feathers, and small intestine. Under our experimental conditions, we recommend that the stocking density of geese should be kept to 5 or fewer birds/m2 to avoid the negative effects of high stocking density on geese.

Effects of dietary fiber on growth performance, slaughter performance, serum biochemical parameters, and nutrient utilization in geese

&NA; We investigated the effects of dietary fiber on growth performance, slaughter performance, serum biochemical parameters, and nutrient utilization in geese. A total of 468 one‐day‐old healthy male Yangzhou goslings with similar body weight were randomly divided into 3 groups with 6 replicates per group and 26 geese per replicate. The geese were then raised for 70 days on diets with a dietary fiber level of 2.5% (Group I), 6.1% (Group III), or 4.3% for d one to 28 and 6.1% for d 29 to 70 (Group II). The geese in Groups II and III had higher body weight, higher average daily gain, and lower ratio of feed to gain compared with those in Group I (P < 0.05 for each comparison). The geese in Groups II and III had greater body‐size measurements (half‐diving length, body length, keel length, and shank circumference), heavier viscera (heart, gizzard, proventriculus, duodenum, jejunum, ileum, and cecum), greater slaughter yield (semi‐eviscerated carcass yield, eviscerated carcass yield, and breast yield), lower serum levels of alanine transaminase, uric acid, and blood urea nitrogen, and higher serum levels of glucose and high‐density lipoprotein compared with those in Group I (P < 0.05 for each comparison). The geese in Groups II and III exhibited greater utilization of energy and crude protein compared with those in Group I (P < 0.05). Taken together, the results suggest that the low‐fiber diet had negative effects on growth performance, slaughter performance, serum biochemical parameters, and nutrient utilization. As herbivorous poultry, geese depend on dietary fiber for normal performance. Dietary fiber is thus an essential nutrient for geese.

Response of growing goslings to dietary supplementation with methionine and betaine

Abstract An experiment with a 2 × 3 factorial design with two concentrations of dietary betaine (0 and 600 mg/kg) and three dietary concentrations of methionine (0, 600 and 1200 mg/kg) was conducted using goslings to estimate growth, nutrient utilisation and digestibility of amino acids from 21 to 70 d of age. Three hundred geese were randomised at 18 d of age into 6 groups with 5 replicates per treatment and 10 geese per replicate. Increasing dietary concentrations of methionine gave a linear increase in body weight and average daily gain. The coefficient of crude fat retention increased as dietary methionine increased and there was a significant non-linear response to increasing dietary methionine. Similarly, increasing supplemental methionine gave linear increases in the digestibility of methionine and cysteine. The results of this study indicated that optimal dietary supplementation of methionine could increase growth performance and methionine and cysteine utilisation in growing goslings. Betaine supplementation had no apparent sparing effect on methionine needs for growth performance, but did improve the apparent cysteine digestibility.

Effects of Dietary Copper on Growth Performance, Slaughter Performance and Nutrient Content of Fecal in Growing Goslings from 28 to 70 Days of Age

A dose-response experiment with four dietary copper concentrations (4.17, 8.17, 12.17 and 16.17 mg/kg) was conducted to estimate the growth performance, slaughter performance, nutrient content of fecal and liver copper concentrations of growing Goslings from 28 to 70 d of age. Two hundred healthy male Yangzhou geese with similar body weight were randomized to four groups with five replicates per treatment and ten geese per replicate. Average daily feed intake, average daily gain and feed conversion ratio of geese for each pen were measured from 28 to 70 d of age. At 70 d of age, two geese were selected randomly from each pen and slaughtered to evaluate carcass quality. Metabolism experiment was conducted with five male geese from each group (one goose per pen) which body weight was close to the mean weight of the group from 64 to 70 d of age. Significant effects of dietary copper was found on body weight, feed conversion ratio, carcass yield, fecal copper concentrations and liver copper concentrations. Body weight, feed conversion ratio and carcass yield showed significant quadratic response to increase dietary copper concentration, while fecal copper concentration and liver copper concentration showed a significant linear response. The result showed that dietary Cu addition can improve growth by increasing the use of the feeding stuff and improving carcass yield in growing Goslings. Furthermore, taking into consideration, the optimal level of Gosling dietary copper was between 8.77 and 11.6 mg/kg from 28 to 70 days of age.

Seasonal and photoperiodic regulation of reproductive hormones and related genes in Yangzhou geese.

&NA; This study aimed at the reproductive endocrine profile under a natural photoperiod in Yangzhou female geese. Geese in the breeding industry were exposed to a natural photoperiod and the results showed the breeding season of Yangzhou geese initiated in autumn, reached peak in February and March, and terminated in June. Fifteen female geese were randomly selected for blood collection samples monthly. The results showed serum luteinizing hormone (LH) concentrations in female geese were higher in the breeding season than in the non‐breeding season. The concentrations of Prolactin (PRL) were also high in the breeding season. Follicle‐stimulating hormone (FSH) concentrations were high from March to May and decreased to low levels in other periods. Furthermore, 6 female birds were selected randomly monthly, sacrificed, and the hypothalamus and pituitary isolated. The expressions of FSH were also high in the breeding season, while the expressions of the gonadotropin‐releasing hormone (GnRH) fluctuated. These results indicated that the reproductive hormones and their transcript expressions were closely related to the reproductive activities in Yangzhou geese.