Desempenho e balanço de nitrogênio de suínos em terminação que receberam dieta restrita ou à vontade, com diferentes teores de lisina

Dois experimentos foram realizados para avaliar a influência de duas porcentagens de lisina associada à restrição alimentar sobre o desempenho e balanço de nitrogênio de suínos em terminação. No experimento I, foram utilizados 48 suínos machos castrados, com média de peso de 76,2±2,3kg, distribuídos em delineamento em blocos ao acaso, em esquema fatorial 2x2 (duas porcentagens de lisina total - normal ou com 30% a mais - e duas formas de arraçoamento - à vontade ou com restrição). Com 28 dias, a porcentagem de inclusão de lisina não influenciou o ganho de peso, mas a porcentagem mais alta resultou em menor consumo e melhor conversão alimentar. A restrição alimentar diminuiu o ganho de peso sem afetar a conversão alimentar. No experimento II, 24 suínos machos castrados, com média de peso de 74,1±2,5kg, foram alojados em gaiolas de metabolismo para receber os mesmos tratamentos. Aos 14 dias de experimento, as dietas não influenciaram a absorção de nitrogênio e a ureia plasmática, porém a dieta ad libitum com a maior porcentagem de lisina reduziu a retenção de nitrogênio. Aos 28 dias, essa mesma dieta aumentou a concentração de ureia plasmática. Conclui-se que o aumento da lisina nas rações melhora o desempenho de suínos machos castrados em terminação, independentemente da forma de arraçoamento, e que a restrição alimentar, nesta fase, não é benéfica.Two experiments were led to evaluate the influence of two percentages of lysine associated to feed restriction over performance and nitrogen balance of finishing barrows. In experiment I, 48 barrows were used, weighing 76.2±2.3kg, distributed in a randomized blocks design in factorial scheme 2x2 (two levels of total lysine - normal or added in 30% - and two feed programs - restricted or ad libitum). At 28 days, the levels of lysine did not influence weight gain, but the higher level provided lesser feed intake and better feed:gain. The feed restriction decreased the weight gain without affecting feed:gain. In Experiment II, 24 barrows, weighing 74.1±2.5kg, were put in metabolic cages to receive the same previously described treatments. At 14 days of the experiment, the diets did not influence the nitrogen absorption and the plasmatic urea, however, the ad libitum diet associated at the higher lysine level reduced nitrogen retention. At 28 days, this same diet increased the plasmatic urea concentration. It was concluded that the increase of lysine levels in diets improves performance in finishing barrows, regardless of the feed program, and feed restriction, in this phase, is not beneficial

Lipid profile and cholesterol of pork with the use of glycerin in feeding

The aim of this work was to evaluate the effects of adding different levels of glycerin in the feeding on the lipid profile and cholesterol of the meat of finishing pigs. The experiment was arranged in a completely randomized design (CRD) with factorial 5x2, being five levels of glycerin in the diet and two genders. Sixty (60) swine of the Topigs genetics (30 barrows and 30 gilts) were used; they presented initial average weight of 79.3+4.0kg and were finished with the weight of 106.2+4.5kg. The levels of glycerin utilized were 0, 50, 100, 150 and 200g/kg in the natural matter. The analyses of lipid and cholesterol profile were conducted in the muscles longissimus dorsi (loin) and semimembranosus (ham) on the left side of the carcasses. Interaction occurred between the levels of crude glycerin in the diet and the sexual category for the profile of fatty acids and cholesterol. On the loin the meat of the barrows presented higher means of C16:0, C16:1, C20:3ω3, C18:1ω9c, Total of saturated (SFA) and monounsaturated (MUFA) fatty acids. On the ham, increased means were found for the fatty acids C18:1ω9c, MUFA, activity of ∆9-desaturaseC18 and ElongaseC16-18 in barrows. The sows' meat presented higher proportions of polyunsaturated fatty acids and of the series ω6 for both the cuts. The amount of cholesterol in the sows' meat presented increase according to the level of glycerin in the meat. The barrows' meat presented indices of atherogenicity greater than the gilts. The levels of glycerin altered the lipid profile and cholesterol content according to the sexual category, promoting a distinct effect on the loin and ham

A predatory mite as potential biological control agent of Diaphorina citri

Diaphorina citri Kuwayama (Hemiptera: Liviidae) is a vector of the bacteria that cause Huanglongbing, the fatal disease threatening citriculture worldwide. One of the most important management methods is the control of D. citri with pesticides, but their intensive use causes development of resistance and pollution. An alternative method is therefore necessary to manage this vector-pathogen system. The generalist predatory mite Amblyseius herbicolus Chant (Acari: Phytoseiidae) can be found on citrus and orange jasmine plants, important hosts of D. citri in Brazil. Here we show that this phytoseiid can reproduce and develop on D. citri eggs. The predation rate was higher on D. citri eggs collected from plants in the field than on eggs from small plants from a laboratory rearing. Yet the predator preferred eggs from the laboratory. This may indicate that the higher predation rate of eggs from the field served to compensate for these eggs being of lower nutritional quality. This was confirmed with a series of experiments with limited numbers of eggs. We conclude that Amblyseius herbicolus is a potential biological control agent of D. citri, and its performance and control may be affected by the quality of the host plant