Plant Products Affect Growth and Digestive Efficiency of Cultured Florida Pompano (Trachinotus carolinus) Fed Compounded Diets

Costs of compounded diets containing fish meal as a primary protein source can be expected to rise as fish meal prices increase in response to static supply and growing demand. Alternatives to fish meal are needed to reduce production costs in many aquaculture enterprises. Some plant proteins are potential replacements for fish meal because of their amino acid composition, lower cost and wide availability. In this study, we measured utilization of soybean meal (SBM) and soy protein concentrate (SPC) by Florida pompano fed compounded diets, to determine the efficacy of these products as fish meal replacements. We also calculated apparent digestibility coefficients (ADCs) for canola meal (CM), corn gluten meal (CGM), and distillers dried grains with solubles (DDGS), following typical methods for digestibility trials. Juvenile Florida pompano were fed fish-meal-free diets containing graded levels of SBM and SPC, and weight gain was compared to a control diet that contained SBM, SPC, and fish meal. Fish fed diets that contained 25–30 percent SBM in combination with 43–39 percent SPC had weight gain equivalent to fish fed the control diet with fish meal, while weight gain of fish fed other soy combinations was significantly less than that of the control group. Apparent crude protein digestibility of CGM was significantly higher than that of DDGS but not significantly different from CM. Apparent energy digestibility of DDGS was significantly lower than CGM but significantly higher than CM. Findings suggested that composition of the reference diet used in a digestibility trial affects the values of calculated ADCs, in addition to the chemical and physical attributes of the test ingredient

Energy Efficiency Choices and Residential Sector: Observable Behaviors and Valuation Models

Over the last decade, households’ preferences about energy efficiency measures in the residential sector have been the focus of a growing body research employing models based on revealed and stated preferences. Analysis of households’ energy consumption and demand elasticities were carried out before with the intent to forecast the potential of energy efficiency programs, but the recent concerns about climate change have drawn attention to the causes of this problem. As a result, the residential and renewable energy sectors have become strategic for the human being’s future. Different retrofit measures and technical solutions are now available for the new buildings, but the existing residential stock is more difficult to improve. More specifically, this implies the investment decision of heterogeneous groups of homeowners and landlords who differ in terms of the characteristics of their assets, their financial possibilities and time preferences. Valuation models have helped to forecast the demand of both market and public goods. Based on different approaches and theories, these applications have opened new avenues of research, but leaving some questions unanswered. This work tries to take stock of a debate that is still open by comparing experiments based on revealed and stated preferences in this specific field