Mechanical site preparation effects on understory plant diversity in the Piedmont of the southern USA

Diversity of understory vegetation was compared among four intensities of site preparation and an adjacent 50-year-old pine-hardwood forest. The study site was a six-year-old loblolly pine (Pines taeda) plantation in the lower Piedmont of Georgia. Species richness and Shannon diversity indices were used to evaluate vine and woody (trees and shrubs) species diversity. Biomass distribution was compared among four plant categories: vines, forbs, grasses, and woody. Moderate intensity treatments (chainsaw and shear and chop) consistently ranked highest overall in diversity, with the mature pine-hardwood forest ranking lowest. Distribution of the four plant categories was not significantly affected by intensity of site preparation.Alabama Agricultural Experiment Station Series No. 9-892325P.     

Association of key foods and beverages with obesity in Australian schoolchildren

OBJECTIVE: To examine the pattern of intake of key foods and beverages of children aged 4-12 years and the association with weight status. DESIGN AND SETTING: A computer-assisted telephone interview was used to determine the intake of fruit, vegetables, packaged snacks, fast foods and sweetened drinks 'yesterday' and 'usually' as reported by parents/guardians of a representative sample of 2184 children from the Barwon South-Western region of Victoria, Australia. RESULTS: Children who consumed >2-3, >3-4 and >4 servings of fruit juice/drinks 'yesterday' were, respectively, 1.7 (95% confidence interval (CI) 1.2-2.2), 1.7 (95% CI 1.2-2.5) and 2.1 (95% CI 1.5-2.9) times more likely to be overweight/obese compared with those who had no servings of fruit juice/drink 'yesterday', adjusted for age, gender and socio-economic status (SES). Further, children who had > or = 3 servings of soft drink 'yesterday' were 2.2 (95% CI 1.3-3.9) times more likely to be overweight/obese compared with those who had no servings of soft drink 'yesterday', adjusted for age, gender and SES. In addition, children who 'usually' drank fruit juice/drinks twice or more per day were 1.7 (95% CI 1.2-2.4) times more likely to be overweight/obese compared with those who drank these beverages once or less per week, adjusted for age, gender and SES. Although fast foods and packaged snacks were regularly eaten, there were no associations between weight status and consumption of these foods. CONCLUSIONS: Intake of sweetened beverages was associated with overweight and obesity in this population of Australian schoolchildren and should be a target for intervention programmes aimed at preventing unhealthy weight gain in children.     

Environmental Conditions and Channel Catfish Ictalurus punctatus Production under Similar Pond Management Regimes in Alabama and Mississippi

This study was conducted to compare water quality and channel catfish production in earthen ponds located in two dissimilar physiographic regions of the southeastern United States and supplied with water of disparate quality. Ponds at Auburn, Alabama are on acidic Piedmont soils and filled with poorly mineralized runoff water; ponds at Stoneville, Mississippi are on slightly alkaline alluvial clays and filled with groundwater of high total alkalinity and hardness. Channel catfish were stocked at 8,750 fish/ha, fed daily, and provided nightly aeration in 0.04-ha ponds at both sites. Ponds were managed as similarly as possible. Minimum daily water temperatures and pH were higher at Stoneville than at Auburn, and there were greater concentrations of suspended clay turbidity, dissolved inorganic phosphorus, total ammonia-nitrogen, and nitrite-nitrogen at Auburn than at Stoneville. The taxonomic composition of the phytoplankton community was broadly different between the two sites. Taste tests revealed off-flavor in fish at both sites, but there were no significant differences (P > 0.05) in flavor scores between sites. The quality of flavor was somewhat different between sites, and these differences in quality were thought to result from observed differences in the taxonomic composition of phytoplankton communities. All differences in water quality seemed to be directly or indirectly related to the dissimilarity in the quality of the water supply and soils at the two locations. Although some water quality variables differed between sites and changed over time at both sites, environmental conditions never deteriorated enough at either site to cause serious stress or mortality in fish. There were no significant differences (P > 0.05) in average net fish production, survival, weight of individual fish at harvest, or feed conversion ratios. Average net fish production and feed conversion ratios, respectively, were 4,905 kg/ha and 1.27 at Auburn and 5,286 kg/ha and 1.27 at Stoneville. The results of this study demonstrate the need for site-specific investigations when conducting certain types of aquaculture research.     

A simple method for calculating liming rates for fish ponds

The pH change in 40 ml of buffer caused by 20 g dry soil may be multiplied by 5600 to provide the lime requirement of mud in a fish pond. The buffer contains 10 g p-nitrophenol, 7.5 g boric acid, 37 g potassium chloride, and 5.25 g potassium hydroxide dissolved and diluted to 1000 ml with distilled water; the buffer pH is adjusted to 8.00.     

Comparison of polyphosphate and orthophosphate as fertilizers for fish ponds

Sodium polyphosphate and triple superphosphate were used as sources of polyphosphate and orthophosphate, respectively, at equal P₂O₅ application rates in sunfish (Lepomis spp.) ponds. Filtrable orthophosphate and total phosphorus concentrations were generally higher in ponds treated with polyphosphate. However, differences between chlorophyll a concentration and net sunfish production did not differ between treatments (P > 0.05).     

Factors affecting respiration in dry pond bottom soils

The potential influence of drying, liming, tilling, bacterial augmentation, and nitrogen fertilization on respiration of pond bottom soil exposed to air between crops was evaluated in laboratory studies using soil respiration chambers. The optimum soil moisture concentration for respiration was 12–20%, and further drying decreased soil respiration. Soil respiration was greatest at pH 7.5–8.0, and both calcium hydroxide and calcium carbonate were effective in enhancing respiration of acidic soil. Pulverization of soil to eliminate the hard surface crust formed on drying accelerated respiration, thus tilling of pond bottom soils would be expected to increase respiration. Nitrogen fertilization showed some benefit to soil respiration, but there was no value in bacterial augmentation. These laboratory findings provide background information useful to pond studies on bottom soil treatments.     

Dietary administration of an LHRH analogue induces spawning of spotted seatrout (Cynoscion nebulosus)

The effects of a single oral administration of des-Gly¹⁰-[D-Ala⁶]-luteinizing hormone-releasing hormone (1–9)-ethylamide (LHRHa) in the diet (0.2–2.5 mg/kg body weight) on ovulation and spawning of spotted seatrout (Cynoscion nebulosus) were examined. Oral administration of 1.0–2.5 mg LHRHa/kg to females in four separate experiments resulted in successful spawning 32–38 h later with mean fertilization and hatching success rates of 93.3% and 74.6%, respectively. A lower dose of LHRHa (0.2 mg/kg) was ineffective in two subsequent experiments. The data suggest that oral administration of 1 mg LHRHa/kg is a reliable method of inducing ovulation in spotted seatrout, resulting in predictable spawning within 38 h of feeding. This noninvasive treatment may be particularly useful for induced spawning of teleosts which are susceptible to handling stress.     

Spatiotemporal distribution of floral resources in a Brazilian city: Implications for the maintenance of pollinators,especially bees

Cities provide resources for the animals that live in them or their surroundings. There has been an increase in the number of ecological studies in urban areas, including interactions between plants and bees. Bees are pollinators that provide a vital ecosystem service to crops and wild plants. We assessed plant community structure in the campus of Universidade de São Paulo in Ribeirão Preto, Brazil, included in the neotropical Atlantic Forest biome, focusing on floristic composition, pollination syndromes, flowering phenology, and spatiotemporal distribution of floral resources for bees. Currently, the city is surrounded by sugar cane plantations. Once a month, from April 2011 to March 2012, we sampled plant species and individuals in bloom in an area with 500 m radius from the bee-rearing facilities of Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP), totaling 78 hectares. We sampled 289 plant species of 73 families; Leguminosae was the richest family. Plants pollinated by bees predominated (67%), followed by plants pollinated by hummingbirds (18%). Melittophilous species flowered throughout the year and, hence, food availability for bees was continuous. The flowering of plant individuals that provided pollen, nectar, and floral oil was seasonal in all vegetation (except for nectar in shrubs), with peaks in resource availability in the transition from the dry to the rainy season, and also in the rainy season. Our results show that the campus is able to maintain bee populations amid a monoculture matrix, acting as a refuge. In addition, it provides a list of several attractive native plants to different pollinator groups, coupled with a phenogram, that can be used in the design and planning of urban areas.     

Effect of colostrum intake on hepatic gluconeogenesis and fatty acid oxidation in the neonatal pig

A total of 24 newborn pigs were used to determine 1) the relationship between the quantity of colostrum consumed and the capacity for gluconeogenesis and fatty acid oxidation and 2) whether fatty acid oxidation limits gluconeogenesis in isolated hepatocytes. Neonatal pigs were obtained prior to nursing and allotted to one of three treatment groups; fed (ad libitum), limit-fed (25% of fed group), or fasted. Hepatocytes were isolated when pigs were 24 h old. Colostrum intake altered the metabolic status of neonates such that the capacity for glucose synthesis and oxidation of octanoate increased with intake. Glucose synthesis with lactate as the substrate was greater (P less than .01) for fed pigs (10.79 mumol glucose.h-1.mg DNA-1) than for either limit-fed (6.56) or fasted counterparts (4.78), which were similar (P greater than .10). Colostrum intake failed to stimulate synthesis from alanine. The oxidation rate for octanoate was similar for fed and limit-fed pigs (.62 and .61 nmol CO2.h-1.mg DNA-1, respectively) but greater (P less than .05) than that observed for fasted counterparts (.36). Oxidation of octanoate (2 mM) was approximately 30-fold greater than for oleate (1 mM); oxidation of the latter was not affected by either colostrum intake or the addition of carnitine (1 mM). The increase in octanoate oxidation, however, did not elicit an increase in glucose synthesis by fasting pigs with either lactate or alanine as precursors. Thus, we conclude that gluconeogenesis is a function of colostrum intake and that reducing equivalents and(or) ATP may not be primary factors limiting glucose synthesis in pigs fasted from birth.