Aplicou-se restrição alimentar qualitativa em frangos de corte, em diferentes fases do crescimento, para reduzir a infiltração gordurosa do fígado e os triglicerídeos plasmáticos, sem influir nas respostas produtivas. Distribuíram-se aleatoriamente 176 pintos machos em quatro tratamentos. As aves foram alojados em baterias (16 gaiolas com 11 aves cada) e foram criados de 1 a 49 dias de idade. No grupo controle as aves foram alimentadas com dieta inicial (1-28 dias) com 3.300kcal EM/kg/dieta e 22,5% de proteína bruta (PB; dieta de crescimento (29-42 dias) com 3.300kcal EM/kg/dieta e 20,9% de PB; dieta de acabamento (43-49 dias de idade) 3.300kcal EM/kg/dieta e 18,2% de PB. As aves nos três grupos sob restrição foram alimentadas com dieta com 2.800kcal de EM/kg/dieta e 24% de PB de 7 aos 14 dias de idade (tratamento 2), de 7 aos 21 dias de idade (tratamento 2) e de 22 aos 35 dias de idade (tratamento 3). Todas as aves dos tratamentos sob restrição foram alimentadas com a dieta controle antes e depois do período de restrição alimentar. Ao final de cada período de restrição foi observada uma maior infiltração gordurosa no fígado (representado pela composição química e escore histológico). Também não houve diferenças entre os triglicerídeos plasmáticos, quando comparado com o controle. Aos 49 dias de idade, o ganho de peso total e a infiltração gordurosa no fígado, foram menores nos grupos restritos. Os níveis de triglicérides plasmáticos, entretanto, foram semelhantes entre os tratamentos, mas reduziram nas aves com aplicação de jejum de 12 horas, quando comparados com aves sem jejum. A baixa relação energia/proteína da dieta afetou o ganho de peso e a infiltração gordurosa no fígado, mas não alterou os valores de triglicérides plasmáticos.

A trial was carried out to evaluate the effect of qualitative restriction at different rearing phases on liver fatness and plasma triglycerides without impairing the productive performance of broiler chickens. One hundred and seventy-six male chicks were randomly assigned to four treatments and reared in battery brooders (16 pens with 11 birds each) from 1 to 49-day-old. In the control group, chicks were fed a starter diet (1 to 28-day-old) with 3,300kcal ME/kg of diet and 22.5% CP; grower diet (29 to 42-day-old) 3,300kcal ME/kg of diet and 18.2% CP; and the finisher diet (43 to 49-day-old) 3,300kcal ME/kg and 18.2% CP. Three restrict groups were fed a low 2,800kcal ME/kg of diet and 24% CP from 7 to 14-day-old (treatment 1); from 7 to 21-day-old (treatment 2); and from 22 to 35-day-old (treatment 3). All treatments were fed control diet before and after the feed restriction period. Feed intake was not affected during the feed restriction period; nevertheless, weight gain was lower (P<0.05) for chicks fed restricted diet from 7 to 21 and from 21 to 35-day-old. At the end of each restriction period, scores of liver for fatty infiltration were higher in restricted birds compared to control birds, although no changes were detected in plasma triglyceride levels. On the 49th day of age, less intracellular fatty infiltration was observed in the liver of previously restricted birds compared to control birds, and weight gain was also lower in the restricted groups. Moreover, triglyceride plasma levels were similar among treatments, but decreased in 12-hour-fasted broilers compared to non-fasted birds. The low energy:protein ratio diet affected weight gain and fatty infiltration in the liver, but had no effect on plasma levels of triglycerides.

The color in salmonids is the main condition for an appropriate trading. This color is a result of the retained pigment incorporated to their diets. The present study was conducted to evaluate the pigmentation degree, color, costs of diets and the productive performance of rainbow trouts fed 25 and 80 ppm of astaxantin (AXT), respectively. A total of 200 chilean trouts (Cofradex variety), with an initial weight of 180 g, were used. They were randomly assigned to 2 treatments with 100 fishes each. The group fed 80 ppm of AXT, was considered the control one, because this was the more common level of inclusion when the assay was run. The productive performance was evaluated considering the average weight, feed consumption, feed conversion efficiency, specific growth rate, mortality, factor of condition, growth percentage and pigment retention percentage. The color intensity was evaluated using the "Colour Chart" and "Colour Salmo-Fan by Roche Lab." The pigmentation, the pigment concentration in the flesh, was evaluated by high resolution liquid chromatography (HPLC). The productive performance results were similar between both treatments (p>0,05), but the pigment retention in the flesh throughout the assay was double in the group fed 25 ppm of AXT as compared with controls (p<0,05). At the end of the trial, the pigmentation values obtained were 20 and 15 ppm of AXT for groups fed 80 and 25 ppm, respectively (p<0,05). The color obtained with both levels of pigment in the diets, were within the minimum required levels for normal commercialization of rainbow trouts fillets. The lower incorporation of AXT allowed a the reduction of 2,2 times in the cost of pigment incorporation in the diets, this result could be an excellent alternative for the producers to improve their efficiency in the world market of cultivated salmonid.

Este trabajo tuvo como objetivo evaluar el grado de pigmentación, coloración, costo económico y la respuesta productiva de truchas arco iris frente al empleo de dos niveles de astaxantina (AXT) en sus dietas, utilizándose 200 truchas nacionales (variedad Cofradex) con un peso inicial de 180 g. Los peces se asignaron al azar a dos tratamientos con 100 truchas cada uno. Un tratamiento utilizó una dieta que incluía 25 ppm de AXT y a los otros se le suministró una dieta con 80 ppm de AXT, siendo este último el tratamiento testigo. La respuesta productiva se evaluó por medio del peso promedio, consumo de alimento, eficiencia de conversión alimenticia, tasa de crecimiento específico, mortalidad, factor de condición, porcentaje de crecimiento y porcentaje de retención. El grado de coloración se evaluó con la Carta Color Roche® y el Abanico Colorimétrico Salmo-Fan Roche®. La pigmentación, concentración de pigmento en el filete, se midió utilizando cromatografía líquida de alta resolución (HPLC). Las respuestas productivas fueron iguales en ambos tratamientos, salvo el porcentaje de retención que aumentó al doble con 25 ppm de AXT. Se alcanzó una pigmentación de 20 y 15 ppm de AXT con los aportes dietarios de 80 y 25 ppm de AXT, respectivamente, la coloración obtenida con los dos tratamientos, se enmarcó dentro de la coloración comercial mínima exigida para truchas arco iris. La incorporación de 25 ppm de AXT en las dietas permitió disminuir 2,2 veces el costo de la incorporación de pigmentos, lo que es una buena alternativa para los productores frente al desafío de elevar su competitividad en el mercado mundial de salmónidos de cultivo

The effect of pelletization or extrusion of a fattening diet fed to rainbow trout (Oncorhynchus mykiss) from 60 ± 5 g up to 270 ± 10 g live weight on productive performance, carcass yield, hepatosomatic index, chemical composition of edible part (fillet ) and economic advantage of both diets was studied. The productive performance was evaluated by the live weight, feed consumption (FC), feed efficiency (FE), specific growth rate and total mortality. The fish fed the extruded diet presented lower FC and a better FE than those fed the pelleted diet (p<0.05), the others parameters were rather similar between the treatments assayed. The carcass yield, hepatosomatic index and chemical composition were not affected (p0.05) by feeding extruded or pelleted diet. The extruded diet presented a lower cost for each kg of live weight or net kg (live weight corrected by carcass yield ) of rainbow trout produced when the FE and the cost of diet were included, with no consideration of the cost of the processes . Feeding an extruded diet to pan size rainbow trout could have some productive advantages expressed by a better FE and a relative lesser cost per total or net kg of trout gained compare to a pelleted diet. Finally as the feed consumption of extruded diet was lower than the pelleted one a lesser amount of residues can be expected with a lower negative environmental impact as well

The biological value of three phosphate feeds and the tissue concentration of some potentially toxic elements were assessed using two raw rock tricalcium phosphates (RRPA and RRPC ), a dicalcium dehydrated phosphate (DPB) and two levels of available P (0.40 and 0.45%), in a 3x2 factorial arrangement of treatments, with one to twenty-one day old broiler chicks. There were no interactions (p 0.05) for the variables measured. DPB was associated, without statistical significance, with faster growth rate and better feed conversion efficiency. DPB had also the highest biological value of the three phosphates. It also presented the highest (p < 0.05) tibia ash and the greatest (p < 0.05) breaking strength. The dietary supplementation of RRPA and RRPC incorporated levels of vanadium (V) in the diets which are considered toxic for poultry. The concentration of V in the kidneys was higher in birds fed RRPC as compared to RRPA and DPB. Based on these and on previous results, the use of raw rock tricalcium phosphates as the only inorganic P supplement in poultry diets is not recommended

Se realizó un estudio tendiente a comparar las respuestas productivas y las concentraciones tisulares de algunos elementos minerales potencialmente tóxicos, cuando pollos broiler machos se alimentaron durante los primeros 21 días de vida con dietas suplementadas con fosfatos rocosos crudos (tricálcicos) o con un fosfato dicálcico monohidratado tratado químicamente. Además, el diseño consideró el empleo de dos niveles de inclusión dietaria de P disponible: 0.40 y 0.45%. Los pollos que recibieron la suplementación de P con fosfato dicálcico mostraron una tendencia a obtener una mayor velocidad de crecimiento y una mejor eficiencia de conversión alimenticia. Así mismo, lograron un valor biológico mayor que el obtenido por las aves alimentadas con los fosfatos tricálcicos rocosos crudos (p0.05). Los pollos alimentados con el producto tratado químicamente, lograron mineralizar mejor sus tibias, las que a su vez presentaron mayor resistencia a la fractura, que las de pollos suplementados con los otros fosfatos (p<0.05). La suplementación dietaria con fosfatos tricálcicos rocosos crudos, incorporó niveles de V a las dietas considerados tóxicos para las aves. La concentración de elementos minerales "contaminantes" en los fosfatos fue directamente replicada en los tejidos estudiados (tibias y riñones), mostrando valores más altos en los fosfatos rocosos crudos. Se concluye que en base a estos resultados y otros previos, no se debería usar un fosfato crudo tricálcico como único suplemento de P en dietas de pollos broiler, sino con otras fuentes de P de alta seguridad y biodisponibilidad