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1.
1. An experiment was conducted with laying hens to determine to what extent sweet white lupins (Lupinus albus, cv Buttercup) could be used as a protein source in their diets.

2. Twenty five individually caged 20 week‐old Hisex laying hens were used per treatment. The hens were housed in a convection house for the duration of the study which lasted 52 weeks. Two diets were formulated, one containing 300 g sweet lupins/kg and the other containing sunflower oil cake and fish meal as protein sources. These diets were blended to obtain seven diets with lupin inclusion rates of 0, 50, 100, 150, 200, 250 and 300 g/k.

3. Results indicated that up to 300 g lupins/kg diet can be fed to Hisex laying hens without a significant effect on egg production, egg mass, efficiency of food utilisation, egg shell thickness, Haugh units or yolk colour. Food intake was however, significantly (P<0.05) positively correlated with lupin inclusion rates.  相似文献   

2.
Precipitation has generally increased in Norway during the last century, and climate projections indicate a further increase. The growing season has also become longer with higher temperatures, particularly in autumn. Previous studies have shown negative effects of high temperatures and, depending upon temperature conditions, contrasting effects of waterlogging on hardening capacity of timothy. We studied effects of waterlogging on seedlings of timothy (Phleum pratense, cv. Noreng) under three pre-acclimation temperatures: 3°C, 7°C, 12°C, and in autumn natural light in a phytotron at Holt, Tromsø (69°N). After temperature treatments, all plants were cold acclimated at 2°C for three weeks under continued waterlogging treatments. Freezing tolerance was determined by intact plants being frozen in pots at incremental temperature decreases in a programmable freezer. Waterlogging resulted in a higher probability of death after freezing, and a significantly reduced regrowth after three weeks at 18°C, 24 hrs light in a greenhouse. Increasing pre-acclimation temperatures also had a clear negative effect on freezing tolerance, but there was no interaction between temperatures and waterlogging. The results indicate that waterlogging may have negative implications for hardening of timothy and may contribute to reduced winter survival under the projected increase in autumn temperatures and precipitation.  相似文献   
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Three fish-loading systems were used to harvest food-size channel catfish (Ictalurus punctatus). Loading rates of equipment and their effect on post-harvest fish survival and weight gain during cool and warm weather were studied.

The turbine pump loading rate (300·7 kg/min) was greater than the lift net (158·00 kg/min) and vacuum pump (54·1 kg/min), while the lift net was greater than the vacuum pump (p < 0·05).

Mean survivals (± SD) for catfish loaded by lift net, turbine pump and vacuum pump from earthen ponds during cool and warm weather were 96·6% (±2·8), 93·9% (±7·4) and 97·7% (±1·1) and 94·0% (±5·7), 85·3% (±8·6) and 89·0% (±12·5), respectively. Mean weight change (± SD) per catfish loaded by the same equipment during cool-and warm-weather tests were −8·2 g/fish (±31·1), −12·4 g/fish (±15·2) and −17·5 g/fish (±19·9), and 67·6 g/fish (±60·6), 33·9 g/fish (±137·4) and 32·4 g/fish (±142·1), respectivley. There were no significant differences among loading systems for survival or mean weight change per fish. The turbine pump is a possible alternative to the traditional life net as a means of loading food-size channel catfish. Further testing on commercial catfish farms is required.  相似文献   

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  1. Isoëtes sabatina is the rarest aquatic quillwort in Europe. Although recently found (2013) in Lake Bracciano (central Italy), the species is just one step away from extinction with an estimated population not exceeding 400 individuals and a spatial range of a few hundred square metres.
  2. Lake Bracciano is a deep, oligo-mesotrophic Mediterranean volcanic lake that has been subjected to human activities. From January to October 2017, the lake experienced a dramatic water level decrease (up to −1.50 m), which significantly affected the littoral zone and the habitat of I. sabatina.
  3. To improve the chances of survival of I. sabatina, the first eco-taxonomic investigation on this species was carried out to describe its genetic distinctness, physical and chemical requirements and companion species.
  4. The phylogenetic position of I. sabatina was investigated by applying standard DNA barcoding methods. Simultaneously, during summer 2019, the physical and chemical features of water and sediments of the I. sabatina population and five small Alpine lakes colonized by Isoëtes echinospora – a supposed close relative – were characterized. These data were then compared with the available data on the trophic requirements of the target obligate aquatic Isoëtes, together with Isoëtes lacustris and Isoëtes malinverniana.
  5. The present survey confirmed the taxonomic and ecological distinctness of I. sabatina – providing the first evidence of genetic differentiation from I. echinospora. Isoëtes sabatina grows in waters with temperature, conductivity and total alkalinity up to 30°C, 561 μS cm−1 and 3.45 meq L−1, respectively.
  6. The edaphic requirements of I. sabatina confirm its outstanding conservation value, and this study offers a basic understanding of how to prevent its extinction. Now, all possible actions must be taken immediately to save this species.
  相似文献   
8.
Sex-linked SSR markers in hemp   总被引:3,自引:0,他引:3  
J. Rode    K. In-Chol  B. Saal    H. Flachowsky    U. Kriese  W. E. Weber 《Plant Breeding》2005,124(2):167-170
Hemp is a dioecious plant with sex chromosomes X and Y, the male sex being heterogametic. The quality of the fibre depends on the sex type. The sex chromosomes can be characterized by molecular markers. In this report, sex‐linked simple sequence repeat (SSR) markers are described. One SSR marker was polymorphic in both the populations derived from single crosses, two other markers in but one of the two populations. Three alleles were detected for two SSR markers indicating polymorphism not only between X and Y, but also between different X chromosomes. In addition, several sex‐linked RAPD markers were detected in one population. Recombination within the sex chromosomes was observed for nearly all markers.  相似文献   
9.
To develop a conceptual understanding of the interaction between tourists and bears, this study examined the responses of brown bears (Ursus arctos) to experimentally introduced tourism at Douglas River in south-central Alaska within the framework of current predator-prey theory. Factors eliciting displacement and the nutritional consequences of behavioral changes were measured. GPS collars were deployed to track temporal and spatial resource use and scan and focal observations were used to quantify foraging efficiency, vigilance behavior, and bear use of various food resources. Total food intake was quantified by combining data on food resource use based on GPS locations and foraging efficiency was measured using spotting scopes from long distances. Seasonal food availability and quality were monitored and utilized as co-variates in comparisons between pre-treatment and treatment years. Though the bear population exhibited significant behavioral differences between the presence and absence of humans, changes in behavior generally mediated effects on total food intake. Adult males at a salt marsh viewing area were the only sex/age class exhibiting reduced food intake resulting from a 15% decline in foraging time when viewers were present. Salmon intake did not differ between pre-treatment and treatment years despite a 10% decline in time spent fishing when viewers were present. The tightly controlled experimental bear-viewing introduced in this study allowed bears to evaluate predation risk associated with human activity and optimally respond to minimize costs due to changes in foraging activities.  相似文献   
10.
OBJECTIVE: To analyse factors associated with breast-feeding and use of sweetened drinks at 12 months, and to compare dietary habits among breast-fed and non-breast-fed infants. DESIGN: Data were collected by a semi-quantitative food-frequency questionnaire filled in by the parents. SETTING: National dietary survey in Norway. SUBJECTS: In total, 1932 12-month-old infants were included. RESULTS: At 12 months, 36% of the infants were breast-fed. The odds of breast-feeding at this age were more than doubled both for mothers > or =35 years compared with mothers <25 years and for mothers in the highest educational group compared with mothers in the lowest. A negative association was found for maternal smoking, and the odds of breast-feeding were 40% lower for mothers who smoked than for non-smokers. Some dietary differences were observed between breast-fed and non-breast-fed infants apart from intake of milk. In particular, breast-fed infants had a significantly lower daily intake of sweetened drinks than non-breast-fed infants and a 16% lower mean daily intake of added sugars (P<0.001). Furthermore, breast-fed infants had 30% higher odds of not receiving sweetened drinks daily, compared with non-breast-fed infants. CONCLUSIONS: Maternal age, education and smoking status were important factors for breast-feeding at 12 months. Breast-fed infants had lower intakes of sweetened drinks and added sugars than non-breast-fed infants. From a public health perspective, continued promotion of breast-feeding is needed to reduce inequalities in breast-feeding. Moreover, prevention of high intakes of sweetened drinks and added sugars should start in infancy.  相似文献   
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