The objective of the study was to evaluate the effects of litter size and supplementation of functional amino acids on the piglet birth weight variability through of a systematic review and meta‐analysis. PubMed, ISI Web of Science, Science Direct, Scopus and SciELO are the main used databases and were searched in January 2019 by using the following keywords and their combinations: within‐litter birth, weight variability, piglets, litter size, sow, amino acids, gestation, uniformity, CV and/or SD. Of the 64 pre‐selected articles, only articles presenting the coefficients of variation and/or standard deviations according to the litter size and different levels of amino acid supplementation in the sow diets during gestation were selected. The average birth weights of total and live piglets were 43% lower in litters from sows with high prolificacy than those from sows with low prolificacy. The weight variability was affected by high prolificacy sows, with increases of 4.04% and 4.54% in the coefficients of variation of total and born alive piglets respectively (p = .074; p = .009). The standard deviation increased by 180 g in born alive piglets to high prolificacy sows. The coefficients of variation of total and live piglets born from high prolificacy sows showed an increase of 4.04% and 4.54% respectively (p = .07; p < .05). There was a tendency for reduced weight variability with amino acids supplementation when considering the standard deviation of total born (p = .072). However, reproductive performance was not significantly influenced (p > .05). In conclusion, the average litter weight and the number of piglets born influence weight variability. Amino acids supplementation may reduce the birth weight variability between piglets. However, this effect depends on the amino acid used, the levels of supplementation and on other factors not completely addressed in this study. Thus, more research is necessary to fully elucidate this topic.

The objective of this study was to evaluate the effect of L-arginine supplementation in lactation diets on the productive and reproductive performance of pluriparous sows and their litters. Seventy-six sows of the same genetic line were assigned to four treatments in a completely randomized design with 19 replicates. The experimental unit was the sow and its respective litter. Treatments comprised a control diet (no L-arginine supplementation) and other three diets obtained by top dressing the control diet with 0.5, 1.0, and 1.5% of L-arginine. L-arginine supplementation had no effect on any performance variables, body condition, milk production, or weaning-estrus interval. There was a quadratic effect on percentage of protein and fat in milk as well as on the daily production of these components. Protein and fat percentage declined during lactation. Adding L-arginine to the diet had a quadratic effect on piglet weight at 13 and 21 days, the optimal level of L-arginine supplementation being estimated as 0.64% and 0.71%, respectively. L-arginine supplementation had a quadratic effect on the weight gain of piglets during the first 13 days and on total period of lactation, the optimal level of L-arginine supplementation being estimated as 0.60% and 0.70%, respectively. Supplementing lactation diets with 0.70% of L-arginine, corresponding to 45 g day⁻¹, improves the weight gain of piglets by improving the nutritional quality of sow milk.

Foi realizado um experimento com o objetivo de avaliar o uso de programas de luz sobre o desempenho e comportamento de suínos em fase de crescimento. O experimento foi conduzido no setor de suinocultura da UFLA, em Lavras, MG, utilizando-se 48 suínos machos castrados com peso médio inicial de 29,99±0,05kg e final de 76,66±0,84kg, alojados em grupos de dois em cada baia, compondo a unidade experimental. Os animais foram distribuídos em delineamento de blocos casualizados, de acordo com o peso inicial em quatro programas de luz, sendo: luz natural (controle-LN); 15 horas de luz e nove de escuro por dia (15L: 9E); 19 horas de luz por dia (19L: 5E); 23 horas de luz por dia (23L: 1E). O experimento teve duração de 45 dias. As variáveis analisadas foram o comportamento dos animais (bebendo, fuçando, ócio e comendo), o desempenho (consumo de ração médio diário, ganho de peso médio diário, conversão alimentar e peso final). O uso de luz suplementar para suínos em crescimento não influenciou o desempenho dos animais.