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Nitrogen Intake (nitrogen + intake)
Selected AbstractsDietary protein requirements of juvenile haddock (Melanogrammus aeglefinus L.)AQUACULTURE RESEARCH, Issue 2001J D Kim Abstract A study was conducted to determine growth and feed utilization by haddock fed diets containing graded levels of protein (35, 40, 45 and 50%). Haddock fingerlings with an average weight of 24 g were hand-fed one of the four isoenergetic (,16.6 MJ digestible energy kg,1) experimental diets to satiation, three times a day during the 9-week period. Filtered and UV-treated water (salinity, 30,) was supplied to each circular tank (holding capacity: 320 L) at 4 L min,1 in a flow-through system. Increases in dietary protein improved weight gain, specific growth rate (SGR) and feed : gain ratio. The highest weight gain (percentage/initial weight) was observed in fish fed 50% protein, although there was no significant difference between groups fed 45% and 50% protein. A similar effect was observed in SGR of fish fed 50% protein, which was the highest among treatments. Although an increase in dietary protein resulted in a slight increase in feed intake, the lowest feed : gain ratio was obtained in fish fed the diet with the highest protein. Nitrogen intake increased from 1.48 to 2.33 g with the increase in dietary protein levels, which resulted in an improvement in whole-body nitrogen gain, although there were no significant differences in nitrogen retention and protein efficiency ratio among fish groups. The broken-line regression of weight gain against protein level yielded an estimated protein requirement of 49.9%. [source] THE POTENTIAL OF TERMINALIA CATAPPA (TROPICAL ALMOND) SEED AS A SOURCE OF DIETARY PROTEINJOURNAL OF FOOD QUALITY, Issue 3 2004C.A. EZEOKONKWO ABSTRACT The nutritional value of Terminalia catappa seed as a source of dietary protein was investigated. The crude protein content of the seed was high (25.81%). The amino acid analysis showed a good pattern of the essential amino acids (EAA) (in g/16 g N) - leucine (7.32), isoleucine (3.58), valine (2.74), phenylalanine (3.04), tryptophan (0.9), methionine (1.48), lysine (3.39), threonine (2.94), histidine (2.96). Tyrosine (2.12) is the limiting amino acid. The protein quality of the seed was evaluated by in vivo bioassays using weanling male Sprague Dawley rats (50,60 g). The indices of protein quality measured include PER, BV, NPU and TD. There were positive correlation between PER and BV (r = 0.7105), PER and body weight gain (r = 0.9157), PER and nitrogen intake (r = 0.7428). The results showed that T. catappa seed protein has a good pattern of the EAA, is highly digestible, can support growth and positive nitrogen balance and thus has a high dietary protein quality. [source] Effects of temporal and spatial variations in food supply on the space and habitat use of red squirrels (Sciurus vulgaris L.)JOURNAL OF ZOOLOGY, Issue 2 2000Peter W. W. Lurz Abstract In non-native conifer plantations characterized by strong spatial and temporal variations in the availability of tree seeds in Spadeadam Forest, northern England, the home range and habitat use of red squirrels Sciurus vulgaris was very flexible. Males tended to have much larger home ranges than females and core-areas of most breeding females seemed mutually exclusive. Adult female red squirrels were found to increase their home range and core-area size in forest patches where food was less abundant. Home-range size was significantly related to home-range quality and the extent of overlap by other females. In contrast with high-quality continuous conifer forests: (1) a considerable proportion of adult males and females at Spadeadam shifted home range, (2) both sexes had much larger home ranges than reported from other habitats in Britain or Belgium. Many ranges were multinuclear, particularly from January onwards, when supplies of seeds become depleted through consumption and seed shed. Squirrels tracked the availability of conifer seeds (lodgepole pine cones throughout the study, Norway spruce cones in spring 1992 and Sitka spruce cones in autumn 1993) and intensively used several non-adjacent activity centres in temporally food-rich patches. Consequently, habitat preference changed markedly with time. The squirrels seemed to maximize nitrogen intake and to avoid the smaller seeds when possible. This resulted in an overall preference for a mixed diet of lodgepole pine and spruce seeds and avoidance of Sitka spruce seeds when Norway spruce seeds were available. These results lend support to the hypothesis of Ostfeld (1985) that when food is sparse and patchily distributed, females should develop intrasexual territoriality, concentrating their activity in food-rich patches, while males should be non-territorial and adapt their space use to the distribution of females. [source] Enterobacteria-mediated nitrogen fixation in natural populations of the fruit fly Ceratitis capitataMOLECULAR ECOLOGY, Issue 9 2005A. BEHAR Abstract Nitrogen, although abundant in the atmosphere, is paradoxically a limited resource for multicellular organisms. In the Animalia, biological nitrogen fixation has solely been demonstrated in termites. We found that all individuals of field-collected Mediterranean fruit flies (Ceratitis capitata) harbour large diazotrophic enterobacterial populations that express dinitrogen reductase in the gut. Moreover, nitrogen fixation was demonstrated in isolated guts and in live flies and may significantly contribute to the fly's nitrogen intake. The presence of similar bacterial consortia in additional insect orders suggests that nitrogen fixation occurs in vast pools of terrestrial insects. On such a large scale, this phenomenon may have a considerable impact on the nitrogen cycle. [source] Winter browsing on Alaska feltleaf willow twigs improves leaf nutritional value for snowshoe hares in summerOIKOS, Issue 1 2003John P. Bryant In boreal forests, browsing by mammals on winter-dormant twigs increases leaf nitrogen, leaf greenness, and leaf size. This suggests browsing reduces competition among meristems for mineral nutrients, and in particular, competition for nitrogen. Winter browsing also reduces the shoot carbohydrate reserves used by leaves to produce condensed tannin. These effects of winter browsing are predicted to improve the nutritional value of leaves for mammals because they increase the mass of digestible nitrogen in leaves. This hypothesis was tested using Alaska feltleaf willow and the snowshoe hare as the experimental system. Six in vivo indicators of leaf nutritional quality were used to compare leaves from winter-browsed plants with leaves from unbrowsed plants. The indicators used were dry matter intake, nitrogen intake, condensed tannin intake, dry matter digestibility, apparent digestibility of nitrogen and nitrogen retention. The results obtained were in agreement with the above hypothesis. In early summer, at the time snowshoe hares and other northern herbivores reproduce, hares fed leaves from browsed plants consumed more nitrogen, digested more of the nitrogen they consumed, and retained more of the nitrogen they digested than did hares fed leaves from unbrowsed plants. The high nitrogen content and low tannin content of leaves from browsed plants may explain this browsing caused increase in leaf nutritional value. How these positive effects of winter browsing on snowshoe hare nutrition at the time of reproduction might affect hare population dynamics are briefly discussed. [source] Influence of replacing brewers' grains with green tea grounds on feed intake, digestibility and ruminal fermentation characteristics of wethersANIMAL SCIENCE JOURNAL, Issue 2 2008Chuncheng XU ABSTRACT An experiment was conducted to examine feed intake, apparent digestibility, nitrogen balance, ruminal fermentation and blood components of wethers fed diets containing increasing levels of wet green tea grounds (WGTG). The experimental design was a 4 × 4 Latin square with four wethers in four 15-day periods. Wethers were allowed access to diets ad libitum, and allotted to one of four treatments in which WGTG replaced 0% (no WGTG added, CTG), 5% (low level, LBG), 10% (medium level, MTG), and 15% (high level, HTG) of total mixed ration (TMR) dry matter (DM) as wet brewers grains (WBG). All TMR silages were ensiled for 120 days and, irrespective of the WGTG addition, they were well preserved with a high lactic acid content, low pH and ammonia-N contents. There were no differences among treatments in feed intake, with the exception of ether extract intake (P = 0.032). Digestibilities for LTG and MTG treatments were not different from CTG. However, the organic matter, crude protein, acid detergent fiber and energy digestibilities for HTG treatment were lower than the CTG (P < 0.05). As the level of WGTG increased, nitrogen intake did not differ, but fecal nitrogen increased (P = 0.002), while urinary nitrogen decreased (P < 0.001). No differences among treatments were found in pH level and volatile fatty acids concentrations. However, the ruminal ammonia-N of the HTG silage was lower than for the CTG silage at all times (P < 0.05). Increasing concentrations of WGTG in the TMR silage decreased (P = 0.019) plasma urea nitrogen content. Therefore, the possible mixing proportion of WGTG for TMR silages can be 10% of the diet DM. [source] | ||||||||||