Existe um grande potencial para a expansão da produção de microalgas, tanto pela variedade de usos quanto pelos produtos que delas podem ser derivados. Dentre esses usos, as características nutricionais e funcionais conferem às algas alto valor biológico para uso em nutrição humana e animal. No entanto, são poucos os estudos que avaliam seu potencial na nutrição de peixes, mais especificadamente de tilápia, um dos principais produtos da aquicultura mundial. O objetivo deste trabalho foi avaliar o potencial de uso de duas espécies de microalgas e o nível ótimo de inclusão da Schizochytrium em dietas para a tilápia. Para tanto, foram realizados ensaios para avaliação do coeficiente de digestibilidade aparente (CDA) de uma microalga rica em proteína, Chlorella sorokiniana, e outra rica em energia, a Schizochytrium sp., ao longo de ensaios de desempenho e digestibilidade de rações contendo níveis crescentes (0%; 1%; 2,5%; 5%; 7,5% e 10%) de Schizochytrium sp. a fim de determinar o nível ótimo de inclusão nas dietas. As microalgas apresentaram altos coeficientes de digestibilidade para a tilápia, com CDA para a proteína de 90,51 e 97,20 % e para energia de 84,22 e 82,55 %, para a Chlorella e Schizochytrium, respectivamente. Os níveis crescentes de inclusão da Schizochytrium alteraram a digestibilidade das rações de forma decrescente para a proteína, passando de um CDA de 88,07 para 86,01, e energia, de um CDA de 74,19 para 67,35. No ensaio de desempenho foi registrado aumento no consumo de ração e piora na conversão alimentar aparente, sem que outros parâmetros de desempenho zootécnico fossem alterados, à medida que aumentava os níveis de inclusão da Schizochytrium na dieta. Não foram registradas alterações nos conteúdos de macro nutrientes na carcaça dos peixes, no entanto, os níveis crescentes de inclusão alteraram o perfil de ácidos graxos aumentando a quantidade de ácidos graxos n-3 no filé, principalmente do ácido docosaexaenoico (DHA), e redução na relação n-6/n-3. Dessa forma, é possível a utilizar Schizochytrium sp. como aditivo nas dietas para alteração do perfil de ácidos graxos da tilápia, enriquecendo os filés com ácidos graxos n-3, com pouco prejuízo nos parâmetros de desempenho. / There is a great potential for expand the microalgae production as by the variety of it uses as for the products and processes which may derive from them. Amongst such uses, nutritional and functional characteristics provide them a high biological value for use in human and animal nutrition. Nevertheless, few studies have evaluated their potential for fish nutrition more specifically tilapia, which is one of the main aquaculture products in the world. The aim of this research was to evaluate the potential use of two microalgae and the optimal level of inclusion of Schizochytrium in diets for tilápia. Therefore, tests were conducted to evaluate the apparent digestibility coefficient (ADC) of microalgae with high protein content Chlorella sorokiniana and another with high energy, Schizochytrium sp. and also performance assay and feed digestibility containing inclusion levels (0%, 1%, 2.5%, 5%, 7.5% and 10%) of Schizochytrium in order to determine the optimum addition level. Both species were very digestible for tilapia with ADCs for protein of 90.51 and 97.20 and for energy 84.22 and 82.55 to Chlorella and Schizochytrium respectively. The increasing levels of inclusion of Schizochytrium changed the digestibility of feed for the protein, through a ADC from 88.07 to 86.01 and for energy from 74.19 to 67.35 ADC. In the growth test as the inclusion of Schizochytrium increased there was an increase in feed intake and feed conversion ratio but any other growth parameters were changed. Regarding the carcass composition, there were no changes in macronutrients composition however, the increasing levels of Schizochytrium altered the fatty acid profile by increasing the amount of omega 3 mainly docosahexaenoic acid (DHA) and reduced the n-6/n-3 ratio. Thus, it is possible to use the Schizochytrium to modify the fatty acid profile of tilápia by incorporating omega 3, with little loss in performance parameters.

Existe um grande potencial para a expansão da produção de microalgas, tanto pela variedade de usos quanto pelos produtos que delas podem ser derivados. Dentre esses usos, as características nutricionais e funcionais conferem às algas alto valor biológico para uso em nutrição humana e animal. No entanto, são poucos os estudos que avaliam seu potencial na nutrição de peixes, mais especificadamente de tilápia, um dos principais produtos da aquicultura mundial. O objetivo deste trabalho foi avaliar o potencial de uso de duas espécies de microalgas e o nível ótimo de inclusão da Schizochytrium em dietas para a tilápia. Para tanto, foram realizados ensaios para avaliação do coeficiente de digestibilidade aparente (CDA) de uma microalga rica em proteína, Chlorella sorokiniana, e outra rica em energia, a Schizochytrium sp., ao longo de ensaios de desempenho e digestibilidade de rações contendo níveis crescentes (0%; 1%; 2,5%; 5%; 7,5% e 10%) de Schizochytrium sp. a fim de determinar o nível ótimo de inclusão nas dietas. As microalgas apresentaram altos coeficientes de digestibilidade para a tilápia, com CDA para a proteína de 90,51 e 97,20 % e para energia de 84,22 e 82,55 %, para a Chlorella e Schizochytrium, respectivamente. Os níveis crescentes de inclusão da Schizochytrium alteraram a digestibilidade das rações de forma decrescente para a proteína, passando de um CDA de 88,07 para 86,01, e energia, de um CDA de 74,19 para 67,35. No ensaio de desempenho foi registrado aumento no consumo de ração e piora na conversão alimentar aparente, sem que outros parâmetros de desempenho zootécnico fossem alterados, à medida que aumentava os níveis de inclusão da Schizochytrium na dieta. Não foram registradas alterações nos conteúdos de macro nutrientes na carcaça dos peixes, no entanto, os níveis crescentes de inclusão alteraram o perfil de ácidos graxos aumentando a quantidade de ácidos graxos n-3 no filé, principalmente do ácido docosaexaenoico (DHA), e redução na relação n-6/n-3. Dessa forma, é possível a utilizar Schizochytrium sp. como aditivo nas dietas para alteração do perfil de ácidos graxos da tilápia, enriquecendo os filés com ácidos graxos n-3, com pouco prejuízo nos parâmetros de desempenho. / There is a great potential for expand the microalgae production as by the variety of it uses as for the products and processes which may derive from them. Amongst such uses, nutritional and functional characteristics provide them a high biological value for use in human and animal nutrition. Nevertheless, few studies have evaluated their potential for fish nutrition more specifically tilapia, which is one of the main aquaculture products in the world. The aim of this research was to evaluate the potential use of two microalgae and the optimal level of inclusion of Schizochytrium in diets for tilápia. Therefore, tests were conducted to evaluate the apparent digestibility coefficient (ADC) of microalgae with high protein content Chlorella sorokiniana and another with high energy, Schizochytrium sp. and also performance assay and feed digestibility containing inclusion levels (0%, 1%, 2.5%, 5%, 7.5% and 10%) of Schizochytrium in order to determine the optimum addition level. Both species were very digestible for tilapia with ADCs for protein of 90.51 and 97.20 and for energy 84.22 and 82.55 to Chlorella and Schizochytrium respectively. The increasing levels of inclusion of Schizochytrium changed the digestibility of feed for the protein, through a ADC from 88.07 to 86.01 and for energy from 74.19 to 67.35 ADC. In the growth test as the inclusion of Schizochytrium increased there was an increase in feed intake and feed conversion ratio but any other growth parameters were changed. Regarding the carcass composition, there were no changes in macronutrients composition however, the increasing levels of Schizochytrium altered the fatty acid profile by increasing the amount of omega 3 mainly docosahexaenoic acid (DHA) and reduced the n-6/n-3 ratio. Thus, it is possible to use the Schizochytrium to modify the fatty acid profile of tilápia by incorporating omega 3, with little loss in performance parameters.

<p>Fat supplementation has potential to improve reproductive performance and increase pregnancy rates in cattle by increasing the energy density of the diet. However, some of the positive effects of fat seem to be influenced by the type of fatty acid fed. Supplementation of omega-3 (n-3) fatty acids increase uptake of n-3 fatty acids into tissue phospholipids and can mitigate immune and inflammatory responses in favor of pregnancy maintenance in cattle. However, n-3 fatty acid supplementation in ruminants has been associated with a decrease in circulating PGF_2α, which may delay CL regression, extend an animal’s time in diestrus, and prevent ovulation. Prostaglandin F_2α is a series 2 prostaglandin, synthesized from omega-6 (n-6) fatty acids, which is inhibited by production of series 3 prostaglandins from n-3 fatty acids. Docosohexaenoic acid (DHA, 22:6n-3) and eicosapentaenoic acid (EPA, 20:5n-3) are long-chain n-3 poly-unsaturated fatty acids (PUFA) that have important biological effects on reproduction through their involvement in hormone and series 3 prostaglandin synthesis. Ruminant tissues are naturally almost devoid of n-3 long-chain PUFA, specifically EPA and DHA. Fish oil is the most common ration additive used to provide very long chain n-3 fatty acids to ruminants. However, marine fish do not synthesize n-3 fatty acids; they consume microscopic algae or other algae-consuming fish to obtain n-3 fatty acids. Algae biomass provides a consistent source of DHA and EPA that could be fed to alter hormonal profiles and improve reproduction of beef heifers. Eighty-eight Angus × Simmental heifers (427 ± 1.8 kg) were blocked by BW and allotted to 2 treatments (44/treatment, 4 pens/treatment, 11 heifers/pen). Control heifers were fed a diet that contained (DM basis) 52.8% mixed grass silage, 32% corn silage, and 15.2% concentrate. DHAgold™ (49% fat; 21.8% DHA; DSM Inc.) was included in the algae diet at 1.65% of DM, replacing equal parts of corn and DDGS. Diets were formulated to contain 12% CP and 0.79 Mcal/kg NEg. Heifers were fed treatment diets from 54 d prior to the breeding season through the first trimester. Follicular fluid was collected on day 47 for hormonal analysis. Artificial insemination (AI) was from d 55 to 98, after which open heifers were removed to 1 control and 1 algae pen and placed with a bull. The study ended on d 180. Performance data were analyzed using the MIXED procedure and conception data were analyzed using the GLIMMIX procedure of SAS. Dominant follicle diameter and follicular estrogen concentration were unaffected by treatment (<i>P</i>≥0.12). Follicular insulin-like growth factor-1 was greater in algae compared to control heifers (<i>P</i>=0.03). During the pre-breeding period, algae supplemented heifers had lesser DMI (<i>P</i>=0.006), and greater ADG (<i>P</i>=0.03) during the breeding period, while BW tended to be greater compared to control heifers on d 98 and 180 (<i>P</i>≤0.07). First service conception rate did not differ between treatments (<i>P</i>=0.67); however, second service tended (<i>P</i>=0.08) and overall conception was (<i>P</i>=0.03) lesser in algae compared to control heifers. These data suggest supplementing DHA-rich algae improved growth, but decreased conception rates of primiparous beef females.</p>