Palma gigante e genótipos resistentes à cochonilha do carmim em dietas para ruminantes

Abstract

Two studies were conducted to evaluate cactus pear genotypes resistant to carmine cochineal in diets for ruminants. In the study conducted with sheep were evaluated the effects of the “Miúda”, “IPA Sertânia”, “Orelha de Elefante Mexicana and “Orelha de Elefante Africana” cactus pear genotypes on intake, digestibility, ruminal parameters, nitrogen balance and microbial protein synthesis and compared with the effects of the “Gigante” cactus pear. Five male castrated sheep (53.2 ± 4.8 kg BW) with rumen cannula were used. The experimental diets contained one genotype of cactus pear (440 g/kg DM), alfalfa hay (585 g/kg DM) and mineral mixture (15 g/kg DM). The diet containing “Gigante” cactus pear (PGG) was the control treatment. There were no differences in the intakes of dry matter (DM), organic matter (OM) and metabolizable energy (ME) for PGG diet and others. The diet containing “Orelha de Elefante Mexicana” cactus pear (PMX) provided higher crude protein (CP) intake. The PGG diet showed lower CP digestibility than diet containing “IPA Sertânia” cactus pear (PST) and PMX diet and lower FDN digestibility than the diet containing “Miúda” cactus pear (PMD) and the PST and PMX diets. The control diet promoted lower ruminal pH than the diet containing “Orelha de Elefante Africana” cactus pear (PAF), lower ruminal ammonia concentration than PST and PMX diets and lower molar proportion of acetate than the diets PMD, PMX and PAF. In the study conducted with lactating dairy cows the same cactus pear genotypes were evaluated, except “Orelha de Elefante Africana” cactus pear. Eight Girolando cows were used, distributed into two 4 x 4 Latin squares. The experimental treatments consisted of a complete feed containing one genotype of cactus pear (440 g/kg DM), sorghum silage (380 g/kg DM), soybean meal (150 g/kg DM ), urea (8 g/kg DM) and mineral mixture (17 g/kg DM). The diet PMD provided greater intakes DM, OM and total digestible nutrients (TDN) than the control diet. Greater CP intake was observed when the PMD and PST diets were provided; a lower non-fibrous carbohydrate (NFC) intake was observed when the PST and PMX diets were provided. The control diet showed lower DM and OM digestibility than PMD and PST and lower CP and NDF digestibility than PMD, PST and PMX. Lower milk, protein, lactose and total solids yield were observed when PST and PMX were supplied. The supply of PMX promoted lower fat-corrected milk yield and milk protein content. The PMX diet provided a greater ratio of unsaturated to saturated fatty acids and a greater proportion of desirable fatty acids. The control diet showed microbial protein synthesis similar to other diets. For sheep and according to the evaluated parameters, it is concluded that the “Miúda”, “IPA Sertânia”, “Orelha de Elefante Mexicana” and “Orelha de Elefante Africana” cactus pear can replace “Gigante” cactus pear. Considering data of intake and performance, the ‘Miúda’ cactus pear is the carmine cochineal resistant genotype that is most suitable to be supplied in diets for lactating cows.