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91.
Journal of Pest Science - The invasive, Halyomorpha halys (Hemiptera: Pentatomidae), is a severe economic insect pest native to East Asia. A strong effort has been made to identify natural egg...  相似文献   
92.
93.
Precision Agriculture - With the rapid advances in precision agriculture technology, machine vision is emerging as a means to obtain accurate spatial information for a control system at relatively...  相似文献   
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Streptococcus suis was isolated postmortem from 2 lambs with a history of lameness. Identity of S. suis was confirmed by species-specific polymerase chain reaction (PCR) and by 16S rRNA gene sequencing. One isolate was untypable by serotyping and non-encapsulated, while the other isolate was serotype 33. The lambs had come from the same farm, and there was no evidence of contact between the lambs and pigs. Although the natural niche for S. suis is considered to be the pig, a wide range of host species may be affected by this pathogen.  相似文献   
96.
Chromium (Cr) is an essential mineral element and has been used in pig diets to improve growth performance, insulin sensitivity, immune response and carcase traits and to reduce heat or other stress responses. The aims of thiss study were to determine the impact of nano-sized chromium tripicolinate (nCrPic) on growth performance, feed efficiency and carcase characteristics of finisher gilts during the summer period. A total of 60 finisher Large White x Landrace gilts were stratified on initial weight and then within strata randomly allocated into two treatment groups in three replicates during mid-summer for 28 days. All pigs were housed in individual pens and had ad libitum access to feed and water. Pigs were fed either a control finisher diet (wheat-based diet containing 13.8 MJ digestible energy (DE) per kilogram and 0.56 g available lysine/MJ DE) or a control diet containing 400 ppb Cr as nCrPic. Dietary nCrPic supplementation increased feed intake by 6 % over the entire study (P?=?0.05). In particular, dietary nCrPic increased average daily feed intake (ADFI) by 8 % (P?=?0.02) during the final 2 weeks of the study. Moreover, dietary nCrPic tended to improve average daily feed (ADFI) over the entire study (P?=?0.09). However, there were no significant effects of nCrPic on feed conversion ratio (FCR), final weight, hot standard carcase weight (HCWT), P2 depth or dressing percentage. Plasma cortisol was decreased by 25 % (P?=?0.06) by dietary nCrPic supplementation. However, there were no effects of nCrPic on plasma glucose, insulin and nonesterified fatty acids (NEFA), might because of the higher feed intake. In conclusion, this study demonstrates that dietary nCrPic supplementation at 400 ppb can increase feed intake in finisher gilts during mid-summer, suggesting that nCrPic can ameliorate some of the negative effects of heat stress in pigs, possibly via decreased of circulating cortisol.  相似文献   
97.
The length of the photoperiod has been implicated as affecting growth of sunshine bass. This study was done to determine if photoperiod length might affect insulin‐like growth factor‐I (IGF‐I), which is a major hormonal regulator of growth in fish. Growth, feed conversion, peritoneal fat content, and plasma concentrations of IGF‐I of sunshine bass were compared on fish held on a short (8 h) or a long (16 h) photoperiod, or after the fish were switched from one photoperiod to the other. Fish were fed daily to apparent satiation for up to 5 wk and were not fed for the last 2 wk of the experiment. Body weight and intraperitoneal fat content increased for the first 2 wk of the experiment and then remained steady for the remainder of the experiment, and feed consumption decreased from 3.5% during the first 2 wk to about 1.5% for the second 2 wk and finally to only 1% during the last week of feeding. Plasma IGF‐I concentrations fell steadily during the entire experiment and was at the lowest level during the last 2 wk when the fish were not fed. There was no consistent effect of the photoperiod in any of the conditions; however, feeding and IGF‐I concentrations were affected by fish density.  相似文献   
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99.
Artemia franciscana were hatched and tested for tolerance to ammonia at pH 6.5 and 8.5 in artificial seawater with a salinity of 17 ‰. Nauplii seemed to be less tolerant of ammonia at pH 6.5 despite the fact that more of the ammonia is in the ionized form (NH4+). It is suggested that this greater sensitivity is a result of the NH4+ competing with the Na+ during gut transfer. Nauplii hatched from decapulated cysts were more tolerant of ammonia than those hatched from whole cysts, probably because of a greater energy reserve.  相似文献   
100.
The interactive effects of salinity and temperature on development and hatching success of lingcod, Ophiodon elongatus Girard, were studied by incubating eggs at four temperatures (6, 9, 12 and 15°C) and five salinities (15, 20, 25, 30 and 35 g L?1). Hatch did not occur in any of the 15°C treatments. Degree days (°C days) to first hatch was not influenced by temperature or salinity, however, calendar days to first hatch differed significantly for temperature (P<0.0001, 61±1, 44±1 and 35±1 days for 6, 9 and 12°C respectively). Degree days to 50% (427.1±4.2) hatch was not significantly influenced by temperature but was by salinity (P=0.0324). Viable hatch (live with no deformities, 74.1±4.0%) was greatest at 9°C and 25 g L?1 but not significantly different in the range of 20–30 g L?1. Larval length (9.4±0.13 mm) was greatest at 9°C and 20–30 g L?1. Temperature and salinity significantly influenced all categories of deformities with treatments at the upper (12°C and 35 g L?1) and lower limits (6°C and 15 g L?1) producing the greatest deformities. The optimal temperature and salinity for incubating Puget Sound lingcod eggs was found to be 9°C and 20–30 g L?1.  相似文献   
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