Rita Flávia Miranda de Oliveira

Effects of sow nutrition during gestation on within-litter birth weight variation: a review

The increasing demand for efficiency in pork production requires great specialization of all sectors involved in this activity. In this context, the development of strategies that could reduce undesirable traits related with negative effects on piglet survival and postnatal growth and development are essential for the pig industry. Currently, special attention is given to variation in birth weight, as some evidences suggest an increased within-litter birth weight variation in modern sows. This variation has been shown to be associated with preweaning mortality, variable weights at weaning and deteriorated growth performance, which results in economic losses and lower efficiency. Therefore, understanding the factors that can influence the events that occur during gestation and that have an impact on the fetal growth and development are important to achieve better efficiency and also to develop strategies that can be used to achieve increased within-litter uniformity of piglet birth weight. This study concludes that even at a given placental size, fetal growth may vary because of differences in placental vascularization and efficiency. Feeding extra feed or energy during late gestation only marginally improves birth weight, and positive effects are not consistent between different studies. The detrimental effects of protein restriction on fetal growth during early gestation may be due to altered placental and endometrial angiogenesis and growth, which leads to a reduction in placental-fetal blood flow, nutrient supply from mother to the fetuses and ultimately to fetal growth retardation. The number of studies that attempted to influence within-litter birth weight variation by means of sow nutrition during gestation is limited. Therefore, more research concerning sow nutrition during gestation associated with the provision of balanced diets to meet requirements of the sows and fetuses are still required. This knowledge may subsequently provide starting points for the design of nutritional strategies that can influence within-litter birth variation.

Effects of dietary protein level and amino acid supplementation on performance of mixed-parity lactating sows in a tropical humid climate

Eighty-six mixed-parity Large White sows were used to determine the effect of diets with reduced CP content or supplemented with essential AA on 28-d lactation performance under humid tropical climatic conditions. This experiment was conducted in Guadeloupe (West French Indies, latitude 16 degrees N, longitude 61 degrees W) between February 2007 and January 2008. Two seasons were distinguished a posteriori from climatic measurement variables continuously recorded in the farrowing room. The average minimum and maximum ambient temperatures and average daily relative humidity for the warm season were 20.5 and 28.2 degrees C, and 93.8%, respectively. The corresponding values for the hot season were 22.7 and 29.4 degrees C, and 93.7%, respectively. The dietary experimental treatments were a normal protein diet (NP), a low protein diet (LP), and a NP diet (NP+) supplemented with essential AA. The NP and LP diets supplied the same levels of standardized digestible Lys (i.e., 0.80 g/MJ of NE), and the NP+ diet supplied 0.95 g/MJ of NE. No interaction between season and diet composition was noted on any response variable evaluated. The ADFI was decreased (P < 0.05) in the hot season (i.e., 3.69 vs. 4.72 kg) and therefore decreased by 500 g per degrees C increase of ambient temperature under high relative humidity conditions. The ADFI tended to be greater with the LP and NP+ diets when compared with the NP treatment (i.e., +10%, P = 0.08). Litter BW gain and mean BW of piglets at weaning were greater (P < 0.05) during the warm season than during the hot season (2.3 vs. 1.8 kg/d and 7.5 vs. 7.1 kg, respectively). Milk production and composition were not affected by dietary treatments but were affected by season (8.1 vs. 6.8 kg/d, for warm and hot seasons, respectively; P < 0.01). The sows fed LP and NP+ diets tended to have decreased backfat thickness losses (3.3 and 3.8 mm, respectively; P > 0.08). In conclusion, the hot season in humid tropical climates, which combines high levels of temperature and humidity, has a pronounced negative impact on performance of lactating sows. Diets with low CP content or supplemented with essential AA can attenuate the effects of hot and humid season by increasing ADFI in lactating sows.

Digestible lysine levels in diets maintaining or not the amino acids relation for broilers from 22 to 42 days of age kept under heat stress

Two trials were conduced to determinate the requirement of digestible lysine of broilers from 22 to 42 days, feeding diets maintaining or not the relationship of amino acids, kept under heat stress. A completely randomized experimental design was used in both trials. In trial 1, the broilers were allotted in five treatments (lysine levels in conventional diets) and six replicates with seven broilers in each. In trial 2, the broilers were allotted in four treatments (diets with different lysine levels, maintaining the relationship of amino acids) and six replicates with seven broilers in each. In both trials, the treatments improved in a linear way the weight gain and feed:gain ratio. However, although the feed:gain ratio had been improved by linear way, the LRP model better adjusted to the data, estimating in 0.92 and 1.022% the level of lysine where occurred a plateau, when it was used the conventional diet and it was considered the relationship of amino acids. There was no effect of treatments on feed intake and on relative and absolute weight of broilers carcass when the relationship of amino acid was maintained or not. The lysine levels increased linearly the absolute weight and yield of breast of broilers, independent of maintained or not the profile of the amino acid. In the trial 1, the absolute and relative weights of thigh and drumstick were not influenced by treatments. The absolute and relative weights of abdominal fat were reduced in a linear way by lysine levels. In the trial 2, the absolute weight of thigh increased linearly with lysine levels of diet. There was no effect of the treatments on absolute and relative weights of drumstick and abdominal fat. It was concluded that male broilers, in the period from 22 to 42 days of age, kept under heat stress require at least 0.955 and 1.022% of digestible lysine in the conventional diet and in the diet maintaining the amino acid profile, respectively.

Níveis de energia metabolizável mantendo a relação lisina digestível: caloria em rações para suínos machos castrados em terminação

Forty barrows from commercial hybrids averaging initial weight of 60.1 ± 1.3 kg were used in a trial to evaluate different ME levels, maintaining the digestible lysine:calorie ratio, on the performance and carcass characteristics. A randomized block experimental design with four treatments, five replicate and two animals per experimental unit was used. The treatments consisted of four ME levels (3,100, 3,230, 3,370, and 3,500 kcal/kg) with 2.41 g of digestible lysine/Mcal of EM ratio. Animals were fed until the end of the experimental period, when the animals reached 95.46 ± 2.89 kg. It was observed linear effect of treatments on feed intake. Feed:gain ratio increased linearly as the ME levels increased. There was no treatment effect on energy efficiency, weight gain, carcass yield, backfat thickness and lean meat yield. It was concluded that increasing ME levels (3,100 to 3,500 kcal/kg, maintaining the dietary digestible lysine:calorie ratio of barrows, increase feed:gain ratio and decrease feed intake with no effect on weight gain and carcass characteristics.

Planos de nutrição para leitoas com alto potencial genético para deposição de carne magra dos 65 aos 105 kg

Ninety and six crossbred gilts with high genetic potential for lean meat gain, with average initial weight of 65.93 ± 2.78 kg and final weight of 105.50 ± 2.18 kg, were used to evaluate the effect of nutrition plans, based on the effects of lysine levels on the carcass traits of gilts in the finishing phase. A randomized block design, with four treatments, 12 replicates and two animals per box, used as experimental unit, was used. The treatments were constituted of nutritional plans (established by sequential lysine levels) for two different weights, from 65 to 95 kg and from 95 to 105 kg. The isoenergy diets and the lysine levels were obtained by changes on dietary corn and soybean proportion. There was no effect of treatments on daily weight gain and daily feed intake. There was effect of nutrition plans on feed:gain ratio, and the nutrition plan 3 showed an increase of 7.86% in relation to nutrition plan 1 and did not differ from the others. Lysine intake increased as the lysine levels of nutrition plans increased. In the nutrition plan 4, lysine intake was 25.43% higher than the other plans. There was no significant difference of nutrition plans on muscle growth ratio, muscle feed:gain ratio, carcass length, backfat thickness in the region between the last and last but one lumbar vertebra, backfat thickness at 6.5 cm from the midline carcass, carcass yield, lean meat yield, fat yield and ham yield. By economic analysis, the nutrition plan 2 showed the best economic return on feed intake. It can be concluded that the nutrition plan 3 (1.00-0.90% lysine) showed the best results of performance and carcass characteristics.

Níveis de lisina digestível em rações, utilizando-se o conceito de proteína ideal, para suínos machos castrados de alto potencial genético dos 15 aos 30 kg

Fourty barrows with high genetic potential for lean gain averaging initial and final body weights of 15.76 + 0.93 kg and 30.23 + 1.56 kg, respectively, were used to evaluate the effect of digestible lysine levels, using the ideal protein concept, on the performance and carcass composition. The treatments were composed of a basal diet containing 19.46% crude protein and 3,280 kcal of ME/kg, that were supplemented with different levels of HCl-L-Lysine, resulting in diets with 0.90, 1.00, 1,10, and 1.20% of digestible lysine. The diets were supplemented with increasing levels of synthetic amino acids, resulting in diets with ratios of methionine + cystine, threonine, tryptophan and valine:lysine constant in 60, 60, 19 e 69%, respectively, based on the true digestibility. No treatment effects on feed intake, concentration of plasma urea and percentages of water, protein and fat in the carcass were observed in this trial. However, significant quadratic effects on weight gain and feed:gain ratio with quadractic maximum and minimum of 1.10 and 1.12% of lysine, respectively, were detected. Intake of digestible lysine increased linearly among treatments. The depositions of protein and fat in the carcass answered quadractily with quadratic maxima at 1.12 and 1.08%, respectively. The level of digestible lysine that provided the best results of performance and carcass characteristics of barrows with high genetic potential from 15 to 30 kg was of 1.12% of true digestible lysine, corresponding to a digestible lysine intake of 12.03 g/day (3.42 g of Lys/Mcal of ME).

Resfriamento do piso da maternidade para porcas em lactação no verão

The effect of cooling the forrowing cage floor on production performance of lactation sows in the summer was evaluated. Forty-two sows from to the 1st to the 5th parturition were allotted to a completely randomized block experimental design with three treatments and 14 repetitions, considering each animal an experimental unit. The treatments were the following: floor not cooled and free intake; floor cooled and 5.5 kg/day of intake; floor cooled and free intake. The sows maintained in cage with cooled floor and fed ad libitum showed greater feed intake, metabolizable energy and digestible lysine. Mobilization of body reserves were greater in sows kept on the cooled floor and receiving restricted food, and they also presented longer interval between weaning and estrus. Piglets of sows kept on cooled floor showed greater weight at weaning and daily weight gain. Lactating sows kept on the cooled floor presented lower values for respiratory frequency, rectal temperature and superficial temperatures of nape, ham and breast. Cooling the farrowing cage floor favors the dissipation of body heat, improving thermal condition, the capacity of feed intake and the productive performance of lactating sows in the summer.

Effects of dietary protein concentration and amino acid supplementation on the feeding behavior of multiparous lactating sows in a tropical humid climate

Forty-seven mixed-parity Large White sows were used to determine the effect of diets with reduced CP content or supplemented with essential AA on 28-d lactation feeding behavior under humid tropical climatic conditions. The study was conducted at the INRA experimental facilities in Guadeloupe, French West Indies (latitude 16 degrees N, longitude 61 degrees W) between February 2007 and January 2008. Two seasons were distinguished a posteriori from climatic measurements continuously recorded in the open-front farrowing room. The average ambient temperature and average daily relative humidity for the warm season were 23.6 degrees C and 93.8%, respectively. The corresponding values for the hot season were 26.1 degrees C and 93.7%. The dietary experimental treatments were a normal protein diet (17.3%), a low protein diet (14.1%), and a normal protein diet supplemented with essential AA (17.6%). No interaction between season and diet composition was found for all criteria. Average daily feed intake was less (P < 0.01) during the hot season (4,559 +/- 161 vs. 5,713 +/- 204 kg/d). Meal size was reduced during the hot season (542 +/- 37 vs. 757 +/- 47 g/meal; P < 0.01). Daily ingestion time (45.5 +/- 3.2 vs. 55.8 +/- 4.0 min/d; P < 0.05) was less in the hot season. Meal size was reduced during the hot season at night (P < 0.01). In both seasons, daily feed intake, feed ingestion, and rate of feed intake were less (P < 0.01) during the nocturnal period than during the diurnal period. The number of meals per day was not affected (P > 0.10) by season or diet composition. Daily feed intake was greater for the sows fed the low protein diet when compared with normal protein treatments (P < 0.05). Duration of standing was not affected by diet or season (P > 0.05), and averaged 126 +/- 35 min/d. This study confirms that feeding behavior variables of the lactating sow are affected by seasonal pavariations of the tropical climate. Irrespective of season, the reduction of CP content improved feed consumption under tropical conditions.

Whole processed (fermented and extruded) soybean and soybean meal in replacement of dried milk in diet of piglets weaned at 14 days of age

The experiment was carried out to evaluate the effect of the use of whole fermented soybean (WFS), whole extruded soybean (WES) and soybean meal (SBM) in replacement to the dried milk (MD) of the diet on the performance, feed intake and morphological alterations on the digestive system of piglets from 14 to 35 day and from 14 to 56 days, and its residual effects from 36 to 56 days of age. Ninety-six crossbreed (Landrace x Large White) piglets weaned at 14 days of age were allotted to a completely randomized experimental design with four treatments, four replicates and six animals per experimental unit. The protein source affected the piglets performance from 14 to 35 days and from 14 to 56 days of ages. The piglets that were fed MD based diet showed better weight gain on the first three weeks after weaning and on the total period. However, from 36 to 56 days of age it was not observed the influence of the treatments on the piglets performance. It was observed effect of protein source on villus height (VH) and villus: cripta ratio of pigs slaughtered at 21 days of age, and on the VH of the piglets slaughtered at 35 days of age; pigs fed MD based diets showed higher VH than other treatments. Whole extrude soybean and SBM can replace the MD in diets of piglets weaned at 14 days of age and that the high level of anti-trypsin factors in the WFS compromised the results.The experiment was carried out to evaluate the effect of the use of whole fermented soybean (WFS), whole extruded soybean (WES) and soybean meal (SBM) in replacement to the dried milk (MD) of the diet on the performance, feed intake and morphological alterations on the digestive system of piglets from 14 to 35 day and from 14 to 56 days, and its residual effects from 36 to 56 days of age. Ninety-six crossbreed (Landrace x Large White) piglets weaned at 14 days of age were allotted to a completely randomized experimental design with four treatments, four replicates and six animals per experimental unit. The protein source affected the piglets performance from 14 to 35 days and from 14 to 56 days of ages. The piglets that were fed MD based diet showed better weight gain on the first three weeks after weaning and on the total period. However, from 36 to 56 days of age it was not observed the influence of the treatments on the piglets performance. It was observed effect of protein source on villus height (VH) and villus: cripta ratio of pigs slaughtered at 21 days of age, and on the VH of the piglets slaughtered at 35 days of age; pigs fed MD based diets showed higher VH than other treatments. Whole extrude soybean and SBM can replace the MD in diets of piglets weaned at 14 days of age and that the high level of anti-trypsin factors in the WFS compromised the results.

Available phosphorus levels in diets for pigs with high genetic potential for lean meat deposition kept in thermoneutral environment from 15 to 30 kg

It was used 72 pigs, 36 castrated males and 36 females, with initial weight of 14.97 ± 0.36 kg to evaluate levels of dietary available phosphorus (aP). The animals were distributed in a completely randomized block design, with six levels of aP (0.107; 0.214; 0.321; 0.428; 0.535 and 0.642%), six replicates and two animals (one castrated male and one female) per experimental unit. Air temperature and relative humidity in the room were kept at 24.5 ± 1.2°C and 76.3 ± 8.5%, respectively. The levels of aP influenced both daily feed intake and daily weight gain, which increased in a quadratic way up to the estimated levels of 0.420% and 0.443%, respectively and feed conversion, which improved in a quadratic manner up to the estimated level of 0.461%. It was observed the effects of levels of aP on quantity of phosphorus and ash in the bone, which increased in a quadratic manner up to the estimated levels of 0.525% and 0.520%, respectively. Levels of Ap affected daily protein deposition in the carcass, which increased in a quadratic way up to the estimated level of 0.394%. There was no effect of levels of aP on daily fat carcass deposition. Levels of aP that provided the best results for daily weight gain, feed conversion and bone mineralization in swines with high genetic potential for lean meat kept in thermoneutral environment, from 15 to 30 kg are 0.443, 0.461 and 0.525%, respectively, corresponding to estimated daily intakes of 5.25, 5.45 and 6.14 g of aP.