An experiment was conducted to compare the effects of increasing dietary net energy (NE) in finishing pig diets while either maintaining a standardized ileal digestible lysine:NE ratio (SID Lys:NE) or maintaining SID Lys as a constant percentage of the diet across increasing energy densities. A total of 150 pigs (Line 600 × 241; DNA, Columbus, NE; initially 35.7 kg) were used in a 91-d study. Pigs were blocked by sex and weight and randomly assigned to 1 of 5 treatments with 2 pigs per pen and 15 pens per treatment. Treatments included a low-energy control diet that was corn-soybean meal-based with added soybean hulls, and a 2 × 2 factorial arrangement of treatments with main effects of increasing dietary NE (medium or high by adding choice white grease) and formulation method (with a SID Lys:NE ratio or maintaining the same percentage SID Lys). Linear and quadratic contrasts were made using the control diet and the medium- and high-energy diets within each formulation method. Pigs and feeders were weighed approximately every 30 d to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F). At the end of the experiment, pigs were sent to a commercial processing facility for carcass data collection. From days 0 to 34 and 34 to 61, ADG and SID Lys intake increased as NE increased (linear, P < 0.05) in pigs fed diets with a Lys:NE ratio, but not for those fed the same percentage Lys. As NE increased, NE intake and G:F increased (P < 0.01) in pigs fed diets with either formulation method. From days 61 to 91, increasing NE had no effect (P > 0.10) on ADG. There was no change in G:F in pigs fed diets with the same percentage Lys (P > 0.10), but G:F decreased then increased (quadratic, P < 0.01) in response to increasing NE in pigs fed diets with a SID Lys:NE ratio. Overall, increasing dietary NE increased (linear, P < 0.001) daily NE intake and G:F (linear, P < 0.018) with either formulation method. However, SID Lys intake, ADG, and hot carcass weight only increased (linear, P < 0.01) when a SID Lys:NE ratio was maintained. Increasing NE without maintaining a constant SID Lys:NE ratio increased backfat depth (quadratic, P = 0.01), whereas it did not in pigs fed diets with a SID Lys:NE ratio. In conclusion, increasing dietary energy density increased NE intake and G:F regardless of formulation method. However, a SID Lys:NE ratio must be maintained to achieve increased ADG and minimize fat deposition.

RESUMO:O Brasil é o quarto maior produtor e exportador mundial de carne suína. Entretanto, a ingestão per capita nacional é baixa quando comparada ao volume anual consumido em outros países. Levando-se em consideração os aspectos nutricionais positivos da ingestão dessa proteína em detrimento daquelas que são mais consumidas, bem como o destaque da eficiência brasileira em todos os elos dessa cadeia produtiva, interessou-se nesta revisão de literatura por identificar as diferentes motivações alegadas pelos consumidores quanto à sua inclusão ou rejeição na dieta. Considerando os aspectos simbólicos ligados à incorporação da "carne de porco", justificados nos artigos pesquisados, concluiu-se necessário que campanhas promocionais sejam pensadas com o objetivo de esclarecer a população quanto às atuais e modernas técnicas de produção, à qualidade nutricional da carne suína, à condição sanitária e à facilidade do seu preparo. Faz-se importante que o comensal perceba a carne suína de modo diferente. Tal percepção será resultado da informação fornecida ao consumidor por meio dos rótulos e campanhas publicitárias. PALAVRAS-CHAVE:Comportamento do consumidor; Consumo de carne suína; Simbolismo. CONSUMPTION OF PORK IN BRAZIL: SYMBOLIC ASPECTS AS DETERMINING FACTORS IN BEHAVIORABSTRACT: Brazil ranks fourth as the greatest world producer and exporter of pork, even though the country´s per capita consumption is low when compared to the

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RESUMO Conduziu-se este estudo com o objetivo de avaliar níveis de energia líquida na dieta de suínos machos castrados em terminação. Foram utilizados 100 suínos, com peso inicial de INTRODUÇÃOA alimentação é o fator de maior custo na produção suinícola e a energia é o componente nutricional responsável pela maior parte deste custo (NOBLET, 1996). O conteúdo energético das rações é um dos componentes nutricionais mais relevantes para o desempenho de suínos na fase de terminação. Portanto, é importante caracterizar o conteúdo energético das dietas e buscar a eficiência na nutrição de suínos, aliando ganhos biológicos e econômicos.Existem diferentes sistemas disponíveis para a caracterização da energia dietética, sendo os mais comuns a energia digestível e metabolizável (ROSTAGNO et al., 2007). Contudo são antigos e incompletos, já que descrevem parcialmente o aproveitamento da energia da dieta pelos suínos. Aliado a isso está o fato de que o constante melhoramento genético dos suínos leva ao aumento das exigências proteicas e energéticas dos animais. Com isso, tornase necessário reavaliar constantemente as exigências nutricionais e as necessidades energéticas dos suínos.A energia líquida tem sido proposta como um sistema mais completo e que descreve de forma mais precisa o conteúdo energético real da dieta, quando comparado aos sistemas de energia digestível e metabolizável (NOBLET & VAN MILGEN, 2004). A energia líquida permite uma estimativa mais acurada dos efeitos da dieta no desempenho dos suínos (MOEHN et al., 2005), pois considera as diferenças de metabolização dos nutrientes (NOBLET, 1996).

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Full-length research article Recent genetic advances have enabled the breeding of pigs with a high capacity for lean tissue deposition, albeit resulting in changes in dietary phosphorus requirements due to variations in the carcass muscle-to-fat ratio. However, metabolism, tissue synthesis, and feed intake differ considerably between growth stages, thereby also changing the pattern of dietary requirements of pigs during their growth stages (Kornegay and Harper, 1997). Thus, because dietary requirements change, the dietary content of digestible phosphorus for swine must be constantly adjusted, and over the years, research studies Non-ruminants

This study evaluated the effects that gradual ractopamine supplementation in diets with nutritional adjustments on pig meat. Were used 80 finishing crossbred barrows in a randomized block design with a 2×5 factorial arrangement (two diets: with and without nutritional adjustment; five levels of ractopamine supplementation: 5-5, 10-10, 20-20, 5-10 and 10-20 ppm) in the 14 initial and 14 final study days, four replicates with two animals by experimental unit. Higher shear force values (P<0.05) were obtained using the 5-5 and 10-20 ppm ractopamine supplementation plans in the diets without nutritional adjustment. With nutritionally adjusted diets, the 5-10 ppm of ractopamine supplementation plan yielded higher shear force values (P<0.05). Water retention capacity was higher (P<0.05) for animals fed adjusted diets and 5-5 and 10-20 ppm of ractopamine plans. In the 10-20 ppm of ractopamine supplementation plan, meat pH was higher (P<0.05) for diets without nutritional adjustment, whereas in the 20-20 ppm of supplementation plan, pH was higher for adjusted diets.

The present study was performed to evaluate the association of chromium-yeast and selenium-yeast as nutritional additives to enhance performance and quantitative characteristics in the carcass of finishing barrows. A total of 48 barrows, commercial hybrid, with initial weight of 68.3±3.5 kg and final weight of 99.6±3.6 kg, were utilized for the study. The animals were distributed in a randomized complete block design, consisting of three levels of chromium-yeast and selenium-yeast (i.e., without supplementation of chromium-yeast and selenium-yeast, supplementation of 0.4 mg kg-1 chromium-yeast and 0.3 mg kg-1 selenium-yeast, and supplementation of 0.8 mg kg-1 chromium-yeast and 0.6 mg kg-1 selenium-yeast) with eight replicates and two animals per experimental unit. The supplementation of chromium and selenium-yeast did not significantly affect (P>0.05) the average daily feed intake, digestible lysine, crude protein and metabolizable energy intake, average daily weight gain, feed conversion, weight and carcass length, back fat thickness, muscle depth, percentage and amount of lean meat, and carcass allowance. These findings suggest that supplementation of chromium and selenium-yeast does not affect the performance or quantitative characteristics in the carcass of finishing barrows.