RESUMO

The excessive accumulation of abdominal fat in broilers is an economic waste. Supplemental dietary L-arginine has been shown to reduce lipogenesis in broilers, but studies on this subject are still scarce. Two experiments were conducted in a 5×2 factorial design, with five L-arginine concentrations in diets (0, 3, 6, 9 and 12 g/kg) provided to male and female broilers, from 29 to 42 days of age, reared in boxes or cages, with six replicates of 23 broilers per box and six replicates of three broilers per cage, totalling 1560 broilers. Data on performance, carcass and cuts yield, abdominal fat deposition, chemical composition of the breast, lipid profile and liver enzyme activity were evaluated in experiment 1. In experiment 2, the balance and retention of nitrogen, metabolizability coefficients and metabolizable energy of feed were determined and the treatments were evaluated in six replicates of three broilers per cage, totalling 180 broilers. In both experiments, there was no interaction (P > 0.05) between L-arginine concentration in the diet and sex of the broilers for all parameters evaluated. Male broilers showed higher (P < 0.05) weight gain, noble cuts yield, levels of CP and mineral matter in the breast, better feed conversion (P < 0.05) and lower (P < 0.05) malic enzyme activity in the liver and abdominal fat deposition. On the other hand, regardless of sex, the increase in L-arginine concentration in the diet improved (P < 0.05) the feed conversion in addition to reducing (P < 0.05) serum levels of total cholesterol and low-density lipoprotein cholesterol, the malic enzyme activity in the liver and abdominal fat deposition. In conclusion, male broilers had better productive results than females. However, supplementing the diet of male or female broilers from 29 to 42 days of age with L-arginine at a concentration of 6.87 g/kg represents a nutritional strategy to improve feed conversion and reduce circulating triacylglycerol and cholesterol levels, NADPH synthesis by liver malic enzyme and abdominal fat deposition, without negatively affecting the carcass and noble cuts yield, the amount of nitrogen excreted by the broilers and the energy value of the feed.

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The present study aimed to evaluate the mechanisms modulated by dietary arginine supplementation to sows during lactation regarding antioxidant capacity and vascularization of mammary glands. At 109 days of gestation, animals were transferred to individual farrowing crates equipped with manual feeders and automatic drinker bowls. Environmental temperature and humidity inside the farrowing rooms were registered every 15 min. At farrowing, sows were assigned in a completely randomized design to a control diet (CON) or the CON diet supplemented with 1.0% L-arginine (ARG). A total of three gilts and two sows were fed the CON diet, whereas three gilts and three sows were fed ARG diets. Sows were fed a fixed amount of 6.0 kg/day, subdivided equally in four delivery times (0700, 1000, 1300 and 1600 h) for 21 days. At weaning, sows were slaughtered and mammary tissue samples and blood from the pudendal vein were collected. Data were analyzed considering each sow as an experimental unit. Differences were considered at P<0.05. L-arginine fed sows presented lower messenger RNA (mRNA) expression for prolactin receptor (P=0.002), angiopoietin1 (P=0.03) and receptor tyrosine kinase (P=0.01); higher mRNA expression for prostaglandin synthase 1 (P=0.01); a trend of decrease for glucocorticoid receptor (P=0.06) and IGF receptor 1 (P=0.07); and a trend (P=0.05) for an increased glutathione peroxidase mRNA expression. The angiopoietin2:angiopoietin1 mRNA ratio tended to increase (P=0.07) in ARG fed sows. L-arginine fed sows had greater (P=0.04) volumetric proportion of blood vessels and a trend of enhance (P=0.07) in the number of blood vessels per mm2. These findings show that 1.0% ARG supplementation to sows activates proliferative mechanisms, may improve mammary tissues' angiogenesis and tended to increase mRNA expression of genes that encode antioxidant enzymes in mammary gland of sows.

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The use of functional amino acids during pregnancy has been linked to improved reproduction in mammals. In this context, arginine is a precursor in the synthesis of numerous molecules, such as nitric oxide and polyamines, which play an important role during reproduction. However, contradictory studies are found in the literature, particularly regarding the amount of supplementation and the period of pregnancy in which it is used. The objective of this study was to evaluate the effects of dietary arginine supplementation for pregnant sows on foetal development via a systematic review. The search for papers was performed during the month of December 2015, in the databases ISI Web of Science, Science Direct, Scopus, and SciELO. From a total of 5675 returned studies, only 13 papers were selected after applying selection criteria. Most (47%) of the studies that evaluated the effects of dietary arginine supplementation on foetal development in pigs used 1% arginine. Supplementation was initiated in the first third of pregnancy in 47% of tests, including in both primiparous and multiparous sows. These studies showed positive results for embryo survival and foetal development, evidenced by the increase in placental weight and the number and weight of piglets born alive. Of all evaluated studies, 53% showed benefits on foetal development. It is concluded that supplementing dietary arginine in gestating sows can benefit embryo survival and foetal development. However, to establish a supplementation plan with this amino acid, aspects related to the period of pregnancy, supplementation levels, and source of arginine must be well defined.

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This experiment was conducted to evaluate the effects of sex and uterus position on swine foetal myogenesis at different gestational ages. Fifteen primiparous sows were divided into three groups according to gestational age: 50, 80, and 106 days. The experiment was a block randomized factorial design with two sexes (male and female) and three uterine regions (apex, middle, and base). After slaughter, each uterus horn was divided into three segments of equal length: apex region near the ovary; base region near the uterine body; and the middle region, lying between the apex and base regions. The foetuses were weighed, identified, and longitudinally opened to harvest the semitendinosus muscle for later morphological analysis. After 50 days of pregnancy, male foetuses had greater (p < .05) weight than females. The number of primary fibres at 50 days of gestation was negatively correlated (r = -.29, p = .04) with the number of foetuses in utero. After 80 days, foetuses in the base region had less (p < .05) secondary area of muscle fibres compared to the apex region, which was accompanied by differences in the weight of the foetuses, the lowest weight were for foetuses located in the base region (p < .05). In the same period, the ratio of secondary to primary fibres had a positive correlation with weight. In conclusion, sex did not influence myogenesis in the gestational ages studied and the development of secondary muscle fibres of the foetuses at 80 days of gestation was affected by their uterine position with foetuses at the base of the uterine horn being less developed.

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Two experiments were conducted to determine the requirement of available P (aP) of pigs selected for high lean deposition during summer (maximum and minimum temperatures of 29.8 ± 3.6 and 21.3 ± 1.1°C, respectively; Exp. 1) and winter (maximum and minimum temperatures of 24.7 ± 2.1 and 9.1 ± 1.6°C, respectively; Exp. 2). Pigs (66.5 ± 2.8 kg, Exp. 1; and 61.1 ± 0.6 kg, Exp. 2) were randomly allotted to 5 dietary treatments. Exp. 1 had 5 pens/treatment and Exp. 2 had 6 pens/treatment, and all pens had 2 pigs. Treatments were composed of a corn-soybean meal basal diet and 4 diets with additional dicalcium phosphate to obtain 5 aP concentrations (0.122, 0.187, 0.252, 0.317, and 0.382% in Exp. 1, and 0.135, 0.200, 0.265, 0.330, and 0.395% in Exp. 2). Pigs were allowed ad libitum access to their respective diets for 30 d. In Exp. 1, increasing aP improved ADFI and ADG (quadratic, P < 0.05), with maximum responses obtained at 0.226 and 0.256% of aP, respectively. Increasing aP improved (P < 0.05) G:F. A broken-line analysis indicated that G:F was maximized (P < 0.05) at 0.295% of aP or 9.04 g of aP/d. Increasing aP also increased (quadratic, P < 0.05) P and Ca (g/kg) in the metacarpals with maximum responses obtained at 0.314 and 0.272% of aP, respectively. The percentage of ash in the metacarpals continued to increase (linear, P < 0.05) with increasing aP. In Exp. 2, ADG and G:F improved (linear and quadratic, P < 0.05) as aP increased in the diet. A broken-line analysis indicated that G:F was maximized (P < 0.05) at 0.316% of aP or 10.58 g of aP per day. However, increasing aP had no effect on ADFI. Percentages of ash, P, and Ca in the metacarpals increased (linear, P < 0.05) with increasing aP. In conclusion, results of this experiment indicated that finishing pigs (60 to 100 kg) kept in a thermoneutral environment require 0.316% aP in the diet (10.58 g/d) to maximize G:F, but the requirement is only 0.295% aP (9.04 g/d) when pigs are under heat stress.

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Avaliou-se o efeito de níveis de treonina digestível em rações sobre o desempenho e características de cacaça de suínos machos castrados, selecionados geneticamente, para deposição de carne na carcaça, na fase de terminação. Foram utilizados 70 animais, com peso inicial de 59,00+1,25kg, distribuídos em delineamento experimental de blocos ao acaso, com cinco tratamentos, sete repetições e dois animais por unidade experimental, sendo que na distribuição dos animais, foi adotado como critério o peso inicial. Os tratamentos foram níveis de treonina na ração (0,480; 0,504; 0,528; 0,554 e 0,572 por cento de treonina digestível). Não houve efeito (P>0,05) dos tratamentos sobre o ganho de peso, consumo de ração e conversão alimentar. Os níveis de treonina digestível não influenciaram (P>0,05) a porcentagem de carne e a espessura de toucinho na carcaça. Conclui-se que o nível de 0,480 por cento de treonina digestível, correspondente a relação de treonina digestível:lisina digestível de 60 por cento, atendeu as exigências de suínos machos castrados de alto potencial para deposição de carne na carcaça dos 60 aos 95kg.(AU)

An experiment was carried out to determine the effects of digestible threonine levels in ration on the performance and carcass traits of hogs genetically selected for lean deposition at finishing. Seventy barrows averaging an initial weight of 59.00+1.25kg were distributed in a randomized experimental block design with five treatments and seven replicates, being two animals per experimental unit. Initial weight was adopted as a criterion for animal distribution in the treatments, which were the levels of digestible treonine in the diet (0.480; 0.504; 0.528; 0.554; and 0.572 percent). No effect (P>0.05) was observed among the treatments on daily weight gain, daily feed intake, and feed conversion. Digestible threonine levels did not influence (P>0.05) lean and backfat thickness percentage. It can be concluded that the level of 0.480 percent of digestible treonine, corresponding to the rate digestible treonine:lysine 60 percent, supplied the requirments of high potential lean deposition barows from 60 to 95kg.(AU)

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RESUMO

Avaliou-se o efeito de níveis de treonina digestível em rações sobre o desempenho e características de cacaça de suínos machos castrados, selecionados geneticamente, para deposição de carne na carcaça, na fase de terminação. Foram utilizados 70 animais, com peso inicial de 59,00+1,25kg, distribuídos em delineamento experimental de blocos ao acaso, com cinco tratamentos, sete repetições e dois animais por unidade experimental, sendo que na distribuição dos animais, foi adotado como critério o peso inicial. Os tratamentos foram níveis de treonina na ração (0,480; 0,504; 0,528; 0,554 e 0,572 por cento de treonina digestível). Não houve efeito (P>0,05) dos tratamentos sobre o ganho de peso, consumo de ração e conversão alimentar. Os níveis de treonina digestível não influenciaram (P>0,05) a porcentagem de carne e a espessura de toucinho na carcaça. Conclui-se que o nível de 0,480 por cento de treonina digestível, correspondente a relação de treonina digestível:lisina digestível de 60 por cento, atendeu as exigências de suínos machos castrados de alto potencial para deposição de carne na carcaça dos 60 aos 95kg.

An experiment was carried out to determine the effects of digestible threonine levels in ration on the performance and carcass traits of hogs genetically selected for lean deposition at finishing. Seventy barrows averaging an initial weight of 59.00+1.25kg were distributed in a randomized experimental block design with five treatments and seven replicates, being two animals per experimental unit. Initial weight was adopted as a criterion for animal distribution in the treatments, which were the levels of digestible treonine in the diet (0.480; 0.504; 0.528; 0.554; and 0.572 percent). No effect (P>0.05) was observed among the treatments on daily weight gain, daily feed intake, and feed conversion. Digestible threonine levels did not influence (P>0.05) lean and backfat thickness percentage. It can be concluded that the level of 0.480 percent of digestible treonine, corresponding to the rate digestible treonine:lysine 60 percent, supplied the requirments of high potential lean deposition barows from 60 to 95kg.

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Utilizaram-se 48 porcas primíparas, de genética PIC, com média de peso de 185,03±15,78kg, para avaliar diferentes níveis de energia digestível (3.350, 3.500, 3.650 e 3.800kcal/kg) na ração, durante a lactação (19,98±1,04 dias). Utilizou-se o delineamento experimental inteiramente casualizado, com quatro tratamentos e 12 repetições, sendo a porca considerada a unidade experimental. O consumo total de ração não variou entre os animais dos tratamentos, sendo que as porcas consumiram em média 4,0kg de ração por dia. O consumo de energia digestível aumentou de forma linear, de acordo com o nível de energia na ração. Não se observou efeito do nível de energia da ração sobre a mobilização de reserva corporal, as características reprodutivas e o nível de insulina no soro das porcas. Observou-se aumento linear do ganho de peso dos leitões em função do consumo de energia das porcas. Conclui-se que porcas primíparas em lactação exigem 3.800kcal/kg de ração, correspondente a um consumo de 14.307kcal/dia.(AU)

Forty-eight primiparous sows (PIC), weighting in average of 185.03±15.78kg, were used to evaluate different levels of digestible energy (3,350; 3,500; 3,650 and 3,800 kcal/kg) during lactation (19.98±1.04 days). A completely randomized design was used with four treatments, 12 replicates, being the sow considered as the experimental unit. The sows were daily fed with 4.0kg of the experimental diet. Energy intake increased linearly, according to the level of digestible energy in the diet. The energy level in the diet did not affect the mobilization of corporal reserve, the reproductive characteristics and the levels of insulin of the serum of the sows. Weight gain of piglets and litter increased linearly, according to the dietary energy levels. It was concluded that primiparous lactating sows need to intake at least 14,307kcal/day.(AU)

Assuntos

RESUMO

Utilizaram-se 48 porcas primíparas, de genética PIC, com média de peso de 185,03±15,78kg, para avaliar diferentes níveis de energia digestível (3.350, 3.500, 3.650 e 3.800kcal/kg) na ração, durante a lactação (19,98±1,04 dias). Utilizou-se o delineamento experimental inteiramente casualizado, com quatro tratamentos e 12 repetições, sendo a porca considerada a unidade experimental. O consumo total de ração não variou entre os animais dos tratamentos, sendo que as porcas consumiram em média 4,0kg de ração por dia. O consumo de energia digestível aumentou de forma linear, de acordo com o nível de energia na ração. Não se observou efeito do nível de energia da ração sobre a mobilização de reserva corporal, as características reprodutivas e o nível de insulina no soro das porcas. Observou-se aumento linear do ganho de peso dos leitões em função do consumo de energia das porcas. Conclui-se que porcas primíparas em lactação exigem 3.800kcal/kg de ração, correspondente a um consumo de 14.307kcal/dia.

Assuntos