ABSTRACT In this work, methodologies for investment appraisal for the period 1975-2018 are examined, particularly in the renewable-energy industry. A body of writings on this subject was critically reviewed with the aim of describing major trends in methodologies for assessing investment processes. It is to be expected that this examination will contribute to the updating of the Cuban social and economic model, which gives priority to, among other things, the renewable energy use.

RESUMEN En el presente trabajo se realiza un análisis del comportamiento metodológico de la evaluación de inversiones en el periodo 1975-2018, con énfasis en el sector energético renovable. En tal sentido, se destaca la combinación de la revisión documental con la reflexión crítica, cuyo objetivo consiste en describir las tendencias fundamentales en materia de metodologías para evaluar el proceso inversionista. Se espera que ello incida en la actualización del modelo económico y social cubano, proceso que señala el uso de las energías limpias como una de las áreas priorizadas.

RESUMO Este trabalho teve por objetivo determinar a composição bromatológica, energética e a digestibilidade ileal de aminoácidos do resíduo seco de destilaria com solúveis (DDGS), além de avaliar o efeito da utilização desse resíduo sobre o desempenho e rendimento de carcaça de frangos de corte dos 22 aos 42 dias de idade. No primeiro experimento, foram utilizadas 48 aves Cobb, machos, com 21 dias de idade e peso médio de 932 g ± 45 g, distribuídas em delineamento experimental inteiramente casualizado (DIC), com dois tratamentos, seis repetições e quatro aves por unidade experimental. No segundo (digestibilidade dos aminoácidos), foram utilizados 12 galos Leghorn cecectomizados, com peso médio de 1.912,1 ± 133,73 g, distribuídos em DIC, com um alimento teste (DDGS), seis repetições e um galo por unidade experimental. Finalmente, foi avaliado o desempenho e rendimento de carcaça de frangos de corte da linhagem Cobb Slow, dos 22 aos 42 dias, sendo utilizados 900 frangos, com peso inicial de 972,50 ± 25,79 g, distribuídos em DIC, em esquema fatorial 2 x 5, totalizando 10 tratamentos (macho e fêmea X 0; 5; 10; 15 e 20% de inclusão de DDGS), com cinco repetições por tratamento. Os valores de energia metabolizável aparente (EMA) e EMA corrigida pelo balanço de nitrogênio (EMAn) foram de 2.461 e 2.282 kcal kg-1, respectivamente. Níveis de 5 a 20% de inclusão de DDGS nas rações promovem queda no desempenho e no rendimento de carcaça de frangos de corte, machos e fêmeas, além de maior deposição de gordura abdominal nas fêmeas.

ABSTRACT The aim of this study was to determine nutritional composition and energy, and ileal digestibility of amino acids, in distiller's dried grains with solubles (DDGS), in addition to evaluating the effect of the use of this residue on the performance and carcass yield of broilers from 22 to 42 days of age. In the first experiment, 48 male Cobb birds, 21 days old, with an average weight of 932 g ± 45g, were distributed in a completely randomized experimental design (CRD), with two treatments, six replicates and four birds per experimental unit. In the second experiment (amino acid digestibility), 12 cecectomized Leghorn roosters, with an average weight of 1,912.1 ± 133.73 g, were distributed in a CRD, with one type of test food (DDGS), six replications and one rooster per experimental unit. Finally, performance and carcass yield were evaluated in Cobb Slow broilers from 22 to 42 days, using 900 chickens with an initial weight of 972.50 ± 25.79 g, distributed in a CRD, in a 2 x 5 factorial scheme, giving a total of 10 treatments (male and female x 0, 5, 10, 15 and 20% addition of DDGS), with five replicates per treatment. The values for apparent metabolizable energy (AME) and nitrogen-corrected AME (AMEn) were 2,461 and 2,282 kcal kg-1 respectively. Adding levels of 5% to 20% DDGS to the feed promotes reductions in performance and carcass yield in male and female broilers, as well as a higher deposition of abdominal fat in females.

RESUMO Foram utilizados 1200 pintos da linhagem Label Rouge, com peso médio inicial de 41,0 ± 0,55 g, distribuídos em um delineamento inteiramente casualizado, em esquema fatorial 2 x 5, (com e sem acidificante X 0, 25, 50, 75 e 100% de silagem de grãos úmidos de milho - SGUM). Foram determinados o ganho de peso (GP), consumo de ração (CR), conversão alimentar (CA), além da análise morfométrica e de microbiota intestinal, rendimento de carcaça e de cortes. De 1 a 63 dias, houve efeito quadrático (P<0,05) da SGUM sobre o CR e CA. Houve interação (P<0,05) entre os níveis de SGUM e a adição de acidificante para o rendimento de carcaça, e de cortes (asa e peito) e fígado das fêmeas. Os machos apresentaram interação (P<0,05) entre os níveis de SGUM e o acidificante para carcaça, sobrecoxa, peito e gordura. Houve interação (P<0,05) da inclusão de SGUM e a adição ou não de acidificante para a contagem de Lactobacillus aos 63 dias. Houve efeito quadrático da SGUM para o tratamento com acidificante, e as criptas apresentaram maior diâmetro para o tratamento sem acidificante. Os resultados sugerem que frangos caipiras alimentados com até 50% de SGUM com acidificante apresentam boas características de carcaça e de cortes e não sofrem danos sobre os parâmetros intestinais.

ABSTRACT In this experiment, 1200 Label Rouge chicks were used, with an average initial weight of 41.0 ± 0.55 g. The chicks were distributed over a completely randomised design in a 2 x 5 factorial scheme (with and without acidifier, and 0, 25, 50, 75 and 100% high-moisture corn silage - HMCS). Weight gain (GP) was determined, together with feed intake (CR), and feed conversion (CA), morphometric analysis, an analysis of intestinal microbiota, and the yield from the carcass and cuts. From 1 to 63 days, a quadratic effect (P<0.05) was seen from the HMCS on CR and CA. There was an interaction (P<0.05) between the levels of HMCS and the addition of acidifier on carcass, cuts (wing and breast) and liver yield in females. For males, there was an interaction (P<0.05) between the levels of HMCS and acidifier on carcass, drumstick, breast and fat. There was an interaction (P<0.05) between the inclusion of HMCS and the addition of acidifier on the Lactobacillus count at 63 days. There was a quadratic effect from the HMCS for the treatment with acidifier, and the crypts showed a greater diameter for the treatment without acidifier. The results suggest that range chickens, fed with up to 50% HMCS with acidifier, display good characteristics for the carcass and cuts, and suffer no damage to the intestinal parameters.

RESUMO: O experimento foi realizado para avaliar o desempenho de frangos de corte nas idades de 1-7 e 8-21 dias de idade, utilizando valores de energia metabolizável do milho, farelo de soja e óleo de soja determinados anteriormente em outro ensaio de metabolismo. Dois estudos foram realizados, divididos em fases de acordo com as idades: pré-inicial (1-7 dias) e inicial (8-21 dias). Em cada estudo, foram utilizados 924 pintos de corte distribuídos aleatoriamente em 42 unidades experimentais, em um delineamento inteiramente casualizado consistindo de cinco dietas utilizando os valores de energia metabolizável aparente corrigida para o balanço de nitrogênio do milho, farelo de soja, e óleo de soja, determinados nos ensaios de metabolismo, e uma dieta com os valores de energia metabolizável dos mesmos alimentos publicados na literatura. No final de cada fase, os animais e as sobras de ração foram pesadas para determinar o consumo de alimento, ganho de peso e conversão alimentar. As dietas com maiores inclusões de óleo de soja mostraram desempenho superior nas diferentes idades. Na fase pré-inicial, apenas a conversão alimentar foi significativa. Na fase inicial, houve diferença significativa para a conversão alimentar e ganho de peso médio e diário.

ABSTRACT: The experiment was carried out to evaluate the performance of broilers in 1-7 and 8-21 days of age, using metabolizable energy values of corn, soybean meal and soybean oil previously determined for each phase in another metabolism trial. Two trails were conducted, divided into phases according to ages: pre-starter (1-7 days) and starter (8-21 days). At each trial were used 924 broiler chicken randomly distributed into 42 experimental units in a completely randomized design with six treatments and seven replications. Treatments consisted of five diets using the values of apparent metabolizable energy corrected for nitrogen balance of corn, soybean meal and soybean oil determined in different metabolism trials, and one diet with the metabolizable energy values of these same ingredients, published on the literature. At the end of each stage, the animals and feed leftover were weighted to determine feed intake, weight gain and feed conversion ratio. Diets with higher soybean oil inclusion, showed superior performance at different stages. At pre-starter only feed conversion ratio was significant (P<0.05). In the initial phase, there was a significant difference (P<0.05) for feed conversion ratio, daily and average weight gain.

It was shown the effect of currency duality elimination and the devaluation of the exchange rate when calculating the necessary working capital in PESCASPIR fishing business, located in Sancti Spíritus, Cuba. It was assessed the necessary working capital taking into account Resolution 19/ 2014 of the Ministry of Finance and Prices with several exchange rates and the reformer index of wholesale prices budgeted for the Ministry above mentioned. It proved that currency unification and devaluation of CUP currency will entail an increase of the necessary working capital in the fishing business.

Se mostró el efecto de la eliminación de la dualidad monetaria y la devaluación del tipo de cambio en el cálculo del capital de trabajo necesario, en la empresa pesquera PESCASPIR de Sancti Spíritus, Cuba. Se calculó el capital de trabajo necesario a partir de la Resolución 19/2014 del Ministerio de Finanzas y Precios, con varias tasas de cambio y el índice reformador de precios mayoristas propuesto por dicho ministerio. Con esto se demostró que la unificación monetaria y la devaluación del CUP en la empresa provocarán un incremento del capital de trabajo necesario en la entidad.

The objective of this trial was to evaluate the bioavailability of DL-2-hydroxy-4-(methyl) butanoic acid (DL-HMBA) and a polyherbal ingredient (PHI) in relation to DL-methionine (DLM) on broilers. Nine hundred male broiler chickens of the Cobb 500 strain were fed from 22 to 42 days of age either a basal diet without industrial methionine supplementation or the basal diet supplemented with DL-HMBA at one of three levels (0.143, 0.286 and 0.429%) or DLM at one of three levels (0.093, 0.186 and 0.279%, each of which is 65% of the respective DL-HMBA level by weight) or PHI at one of the same three levels used for DLM (0.093, 0.186 and 0.279%). The weight gain, feed conversion ratio and relative weights of breast and abdominal fat were improved over that of basal diet-fed broilers by the addition of DL-HMBA and DLM to the diet. A simultaneous exponential regression analysis revealed that the relative bioavailability values for DL-HMBA and PHI were 52% and 5% of that of DLM, respectively, for weight gain, and 57% and 4%, respectively, for feed conversion ratio. Concerning breast meat yield, a simultaneous linear regression analysis (slope ratio) showed that the relative bioavailability for DL-HMBA was 65% of that of DLM. Considering all studied parameters together, the relative bioavailability values for DL-HMBA and PHI are 58% and 4.5% of that of DLM on a product basis.