Ontogeny of IGF-I responsiveness to bGH in young lambs

The ontogeny of hepatic growth hormone (GH) receptors (GHR), as measured by responses of both plasma insulin-like growth factor-I (IGF-I) and hepatic GHR to an exogenous bGH stimulus, was examined using sheep of different ages (Days 1-7, 14-21, 28-35, and 56-63 of life, and yearlings). The IGF-I response to bGH was first examined in yearling sheep using two doses of bGH (0.1 and 0.2 mg/kg LW/d). Based on these results, lambs in four groups up to Day 63 of life were treated for 5 d with bGH (n = 10) at a dose of 0.15 mg/kg LW/d or with saline (n = 10). Jugular blood samples were taken once daily on Days - 1, 4, and 5 of treatment. bGH treatment in lambs up to Day 63 of life had little effect on plasma concentrations of GH, insulin, glucose or urea, but significantly (P < 0.05) increased circulating concentrations of IGF-I at all ages and of NEFA at Day 62/63 of life. In contrast, bGH treatment at either dose in yearlings significantly increased these parameters, except for plasma urea concentrations which were decreased in bGH-treated yearlings. However, the responses of plasma IGF-I concentration to bGH stimulus in lambs up to Day 63 of life were small compared to those in yearling sheep. Consistent with this, bGH treatment failed to affect hepatic GH binding in young lambs, but up-regulated it in yearling sheep. Furthermore, basal (unstimulated) GH binding did not differ between sheep of 7 vs. 63 vs. 365 d of age, despite the greater IGF-I responses to bGH in the latter group. It is suggested that hepatic GHR in lambs up to Day 63 of life are not fully functional compared to the situation in yearlings.     

Effects of fungal (Aspergillus niger or Ceriporiopsis subvermispora) fermentation on the nutritive value of shea nut (Vitellaria paradoxa) meal for broiler chicks

1. Shea nut (Vitellaria paradoxa Gaertn.) meal was fermented for 8 d with either Aspergillus niger, Ceriporiopsis subvermispora or a mixture of the two organisms. The fermentation was completed using two methods, an opened container or a closed container. 2. Each of the 6 samples was dried and incorporated into basal broiler diets at 90 g/kg. 3. In addition, the unfermented shea nut meal was incorporated in the diet at 90 g/kg and the basal diet (maize and soybean meal based) was also provided as an eighth dietary treatment to individually caged broiler chickens. 4. All fermented fungi-treated shea nut meals had similar proximate nutrient compositions to the unfermented shea nut meal, but there were substantial decreases in their hydrolysable tannins and saponin contents. Both fermentation methods gave similar reductions in the concentrations of tannins and saponins. 5. Shea nut meal fermented with individual or both fungal organisms gave greater (P < 0.001) growth performance than that of unfermented shea nut meal. However, all shea nut meals including the unfermented meal gave lower (P < 0.001) growth variables than those for the maize-soybean meal control. 6. The nutritional improvement of shea nut meal achieved in this study still falls far short of what is expected for it to become valuable for the poultry feed industry. These fermentation methods using A. niger or C. subvermispora require further improvements to provide satisfactory feed products.     

Dynamic changes in American lobster suitable habitat distribution on the Northeast U.S. Shelf linked to oceanographic conditions

American lobster (Homarus americanus) supports one of the most valuable regional fisheries in the United States, with its abundance and distribution profoundly influenced by environmental conditions. To explain how lobster distribution has changed over time and assess the role of environmental variables on these changes, we used random forest classification and regression tree models to estimate occupancy and biomass in two seasonal periods. The occupancy models were fit to static and dynamic variables, which yielded model fits with AUC scores of 0.80 and 0.78 for spring and fall, respectively. Biomass models were fit with the same data and resulted in models explaining 61% and 63% of the spring and fall biomass variance, respectively. Significant variables scored in the formation of the regression trees were secondary productivity (i.e., zooplankton), bathymetry characteristics, and temperature. American lobster suitable habitat has changed regionally; habitat has increased in the Gulf of Maine and declined in Southern New England. There is also evidence of declining habitat along the inshore margin of the Gulf of Maine, which has been accompanied by a shift in occupancy probability offshore. Habitat suitability results from the random forest models provide insights on the structure and function of lobster habitat and context to understand recent population trends.     

Quartz: synthesis at Earth-surface conditions

Quartz has been crystallized directly from seawater at room temperature. This is the first time that identifiable quartz has been synthesized in aqueous solution at earth-surface conditions without the aging of an original amorphous precipitate. The concentration of dissolved silica in equilibrium with quartz at 20 degrees C and 1 atmosphere is 4.4+/-0.3 parts per million, a value in agreement with the theoretical value obtained by a constant heat capacity fit of higher temperature equilibrium data. This experiment confirms the results of petrologic investigations which suggest that quartz precipitates directly from aqueous solution during chemical weathering and early diagenesis.     

The distrubution of Herbst corpuscles in the beak of the domestic fowl

Histological examination of a series of sections of beaks of domestic fowl has demonstrated the presence of Herbst corpuscles of two size ranges in the corium of the rhinotheca and hard palate respectively. These are distributed over the lateral surface of the body of the premaxillary bones in a broad band and beneath the lateral ridges of the hard palate. They extended as far anterior as the anterior apex of the premaxillary bones.