A longitudinal and prospective study was carried out at two stateoperated maternity hospitals in Belo Horizonte during 1996 in order to assess the weight of preterm appropriate-for-gestational-age newborns during the first twelve weeks of life. Two hundred and sixty appropriate-for-gestational-age preterm infants with birth weight <2500 g were evaluated weekly. The infants were divided into groups based on birth weight at 250-g intervals. Using weight means, somatic growth curves were constructed and adjusted to Count's model. Absolute (g/day) and relative (g kg -1 day -1 ) velocity curves were obtained from a derivative of this model. The growth curve was characterized by weight loss during the 1st week (4-6 days) ranging from 5.9 to 13.3% (the greater the percentage, the lower the birth weight), recovery of birth weight within 17 and 21 days, and increasingly higher rates of weight gain after the 3rd week. These rates were proportional to birth weight when expressed as g/day (the lowest and the highest birth weight neonates gained 15.9 and 30.1 g/day, respectively). However, if expressed as g kg -1 day -1 , the rates were inversely proportional to birth weight (during the 3rd week, the lowest and the highest weight newborns gained 18.0 and 11.5 g kg -1 day -1 , respectively). During the 12th week the rates were similar for all groups (7.5 to 10.2 g kg -1 day -1 ). The relative velocity accurately reflects weight gain of preterm infants who are appropriate for gestational age and, in the present study, it was inversely proportional to birth weight, with a peak during the 3rd week of life, and a homogeneous behavior during the 12th week for all weight groups.

-This study was developed to evaluate the effects of adding L-glutamine and L-glutamate in diets with no lactose or with 4.0 or 8.0% lactose inclusion for piglets weaned at 21 days old. One hundred and eight piglets with initial weight of 6.12±0.70 kg were allotted in a complete randomized block design, in a 3 × 2 factorial arrangement, with six treatments, six replicates, and three piglets per experimental unit. The experimental diets were supplied from 21 to 35 days. From 36 to 49 days, animals received the same diet with no lactose inclusion, but the animals in the treatments with L-glutamine + L-glutamate in the previous phase continued to receive diets containing these ingredients. There was no interaction between the level of lactose and the inclusion of L-glutamine + L-glutamate on the parameters evaluated. The levels of lactose did not affect the performance of piglets in either of the two periods. Adding L-glutamine and L-glutamate in the diet positively influenced the weight gain of pigs from 21 to 49 days of age and increased the villous height in the duodenum, jejunum and ileum. Inclusion of L-glutamine + L-glutamate in diets for piglets weaned at 21 days of age improves the performance and the intestinal mucosa morphology, regardless of lactose addition.

The objective of this study was to evaluate the effect of different levels of arginine in the diet of Japanese quails and to determine which provides the best egg production indices. We used 400 birds with an initial average weight of 180 g at 140 days of age. These were distributed among experimental units in a randomized design. Five levels of digestible arginine were studied (1.148, 1.256, 1.364, 1.472, and 1.580%) in reference to a fixed level of digestible lysine (1.083%; for arginine to lysine ratios of 1.06, 1.16, 1.26, 1.36, and 1.46). Each treatment was replicated 10 times for a total of 50 experimental units, each with eight quails. Feed rations, leftovers, and dead animals were weighed to calculate and adjust performance parameters. The variables analyzed were: daily feed intake (DFI), egg laying rate (ER), average egg weight (EW), total egg mass (EM), feed conversion per egg mass and per dozen eggs (FCEM and FCDE), yolk, skin, and albumen weights (AYW, ASW and AAW), relative weights of yolk, albumen and shell (RYW, RAW and RSW), the Haugh unit (HU), and the percentage of eggs suitable for market (EP). The variables associated with performance and internal and external quality were not affected (P > 0.05) by different levels of arginine, except for EP, which decreased linearly (P = 0.009) with increasing arginine according to the equation: Ŷ = -3.44x + 103.13, r² = 0.94. We conclude that the best concentration of arginine in quail diets is 1.148%, corresponding to an arginine to lysine ratio of 1.06. Key words: Antagonism. Poultry. Amino acid imbalance. ResumoObjetivou-se avaliar o efeito de diferentes níveis de arginina digestível e determinar aquele que proporciona os melhores índices produtivos em dietas para codornas japonesas em postura. Foram utilizadas 400 aves com peso médio inicial de 180 gramas aos 140 dias de idade, distribuídas nas unidades experimentais em delineamento inteiramente casualizado. Foram utilizados cinco níveis crescentes de arginina digestível (1,148; 1,256; 1,364; 1,472; 1,580%) sob um nível fixo de lisina digestível de 1,083%, correspondendo à relação arginina: lisina digestível de (1,06; 1,16; 1,26; 1,36; 1,46), portanto, foram cinco tratamentos com dez repetições cada, num total de 50 unidades experimentais. Cada unidade experimental continha oito codornas. As rações, as sobras e os animais mortos eram pesados a fim de se calcular e ajustar os parâmetros de desempenho. As variáveis analisadas foram: consumo de ração diário (CRD), taxa de postura (TP), peso médio dos ovos (PO), massa dos ovos (MO), conversão alimentar por massa de ovos e por dúzia de ovos (CAMO e CADO), pesos da gema, casca e albúmen (PG, PC e PA), pesos relativos da gema, da casca e do albúmen (PRG, PRC e PRA), além da unidade Haugh (UH) e percentual de ovos comercializáveis (OC). As variáveis de desempenho e de qualidade interna e externa de ovos em análise não foram afetadas (P>0,05) pelos diferentes níveis de arginina, a exceção do parâmetro ovos comercializáveis que decresceu linearmente (P=...

-Ninety-six barrows from 63 to 103 days of age were used to evaluate the effects of dietary digestible lysine levels on performance and carcass traits of two genetic lines selected for lean deposition. Pigs with initial body weight of 23.800 ± 1.075 kg were allotted in a completely randomized block design, within a 4 × 2 factorial arrangement (four digestible lysine levels: 0.80, 0.90, 1.00, 1.10%, and two genetic lines), with six replicates and two pigs per experimental unit. There was no interaction between genetic and digestible lysine levels. The digestible lysine levels also did not influence performance or carcass traits of pigs; however, average daily lysine intake increased with increasing digestible lysine level in the experimental diets. Pigs from genetic line B had better carcass traits when compared with those from genetic line A. The level of 0.80% digestible lysine corresponding to a daily intake of 16.60 g digestible lysine meets the nutritional requirement of pigs from both genetic lines evaluated, from 63 to 103 days of age.

The objective of this study was to evaluate the existence of an interaction between lysine and arginine, and to determine their optimal ratio in the diets of Japanese laying quails. We used 480 quails with an initial mean weight of 180 g at 140 days of age. The quails were distributed in the experimental units in a completely randomized (3 × 2) factorial design, with three levels of digestible lysine (1.083, 1.183, 1.283%) and two levels of digestible arginine (1.472 and 1.580%). There were six treatments, with 10 replicates each, for a total of 60 experimental units. Rations, leftovers, and dead animals were weighed in order to calculate and adjust performance parameters. The variables analyzed were: daily diet consumption (DDC), laying rate (LR), average egg weight (AEW), egg mass (EM), feed conversion per egg mass and dozen eggs (FCEM and FCDE, respectively), weights of yolk, eggshell, and albumen (YW, ESW, and AW, respectively), relative yolk, eggshell, and albumen weights (RYW, RESW, and RAW, respectively), Haugh unit (HU), and marketable egg percentage (ME). There was no interaction (P > 0.05) between the levels of digestible lysine and arginine on the parameters analyzed; independently, these parameters were not affected by lysine and arginine levels. In conclusion, the optimal ratio of lysine and arginine in the diet of laying quails was 1.36: 1.00, which was the lowest used in the present study. Key words: Amino acids. Poultry. Amino acid interaction. ResumoObjetivou-se avaliar a existência de interação aminoacídica entre lisina e arginina, assim como, determinar a melhor relação entre eles em dietas para codornas japonesas em postura. Foram utilizadas 480 codornas com peso médio inicial de 180g aos 140 dias de idade. As codornas foram distribuídas nas unidades experimentais em delineamento inteiramente casualizado esquema fatorial (3x2) no qual foram utilizados três níveis de lisina digestível (1,083; 1,183; 1,283%) e dois níveis de arginina digestível (1,472 e 1,580%). Totalizando seis tratamentos com dez repetições cada, num total de 60 unidades experimentais. As rações, as sobras e os animais mortos foram pesadas a fim de calcular e ajustar os parâmetros de desempenho. As variáveis analisadas foram: consumo de ração diário (CRD), taxa de postura (TP), peso médio dos ovos (PO), massa dos ovos (MO), conversão alimentar por massa de ovos e por dúzia de ovos (CAMO e CADO), pesos da gema, casca e albúmen (PG, PC e PA), pesos relativos da gema, da casca e do albúmen (PRG, PRC e PRA), além da unidade Haugh (UH) e percentual de ovos comercializáveis (OC). Não houve interação (P>0,05) entre os níveis de lisina e arginina digestível sobre os parâmetros em análise, de maneira independente os níveis de lisina e de arginina também não afetaram os parâmetros em análise. Concluiu-se que a melhor relação de lisina e arginina para codornas em fase de postura foi a menor em estudo: 1,36:1,00. Palavras-chave: Aminoácidos. Aves. Interação aminoacídica.