Much of our understanding of energy metabolism in the pig has been derived from studies in which the energy supply was controlled through regulated feed intake. In commercial situations, where ad libitum feeding is practiced, dietary energy concentration, but not daily feed intake, is under producer control. This study evaluated the interactive effects of dietary energy concentration and feeding level (FL) on growth, body composition, and nutrient deposition rates. Individually penned PIC barrows, with an initial BW of 9.5 ± 1.0 kg, were allotted to 1 of 9 treatments in a 3 × 3 factorial arrangement plus an initial slaughter group (n = 6) that was slaughtered at the beginning of the trial. Three NE concentrations (low, 2.15; medium, 2.26; and high, 2.37 Mcal of NE/kg) and 3 feeding levels (FL: 100, 80, or 70% of ad libitum access to feed) were investigated. Daily feed allowance for the restrictedfed pigs was adjusted twice per week on a BW basis until completion of the experiment at 25 ± 1 kg of BW. Average daily gain, ADFI, and G:F were unaffected by NE (mean = 572 g, 781 g, and 0.732 g/g, respectively). Average daily gain and ADFI, but not G:F, increased (P < 0.05) with FL. Empty body lipid concentration

. 2007. The effect of dietary energy concentration and total lysine/digestible energy ratio on the growth performance of weaned pigs. Can. J. Anim. Sci. 87: 45-55. Amino acids should be defined in relation to dietary energy concentration in diets for young pigs. However, the literature contains diverse estimates of the optimum lysine:digestible energy (DE) ratio for weanling pigs performing at levels commonly observed in commercial practice. Further, there is a poor understanding of the reponse of the weanling pig to dietary energy concentration. A growth experiment was conducted to define the optimum total lysine:DE ratio for pigs from 4 to 8 wk of age. Dietary treatments were arranged as a 2 × 5 factorial: low (LDE, 3.4 Mcal kg -1 ) or high DE (HDE, 3.6 Mcal kg -1 ) and the following total lysine:DE ratios: 3.7, 4.0, 4.3, 4.6, or 4.9 g Mcal -1 ). The experiment ran for 28 d, beginning 7 d post-weaning, using four pigs per pen and six pens per diet for a total of 240 pigs (27 ± 2 d; 7.5 ± 1.1 kg). No DE × lysine:DE ratio interactions were detected for any performance parameter (P > 0.05). The average daily feed intake (ADFI) was 4% greater with pigs on LDE than HDE diets (DE, P < 0.05), but was not affected by lysine:DE ratio (P > 0.05). Conversely, DE did not affect average daily gain (ADG) (P > 0.05), but increased quadratically (day 0 to 14; P < 0.05) and (day 0 to 28; P < 0.10) with increasing lysine:DE ratio. Feed efficiency increased linearly with increasing lysine:DE ratio (P < 0.05) and was 4% greater with the HDE than LDE diets (P < 0.05). The optimum total lysine:DE ratio for ADG was determined to be 4.46 and 4.27 g Mcal -1 for pigs between 7.5 to 13 kg and 7.5 to 22.5 kg BW, respectively.Key words: Pig, total lysine, digestible energy, growth Oresanya, T. F., Beaulieu, A. D., Beltranena, E. et Patience, J. F. 2007. Incidence de la concentration d'énergie dans les aliments et du ratio lysine totale/énergie digestible sur la croissance des porcs sevrés. Can. J. Anim. Sci. 87: 45-55. Pour pré-parer les rations des porcelets, les acides aminés devraient être définis en fonction de la quantité d'énergie que renferment les aliments. Malheureusement, dans la documentation, les estimations du ratio optimal entre la lysine et l'énergie digestible (ED) varient pour les porcs sevrés croissant aux taux couramment observés dans les élevages commerciaux. Par ailleurs, on saisit mal la réaction du porc sevré à la concentration d'énergie digestible. Les auteurs ont entrepris une étude sur la croissance afin d'établir le ratio lysine totale:ED idéal pour les porcs de 4 à 8 semaines. Les régimes ont été répartis selon une disposition factorielle de 2 × 5, à savoir faible (LED, 3,4 Mcal par kg) ou forte concentration de ED (HDE, 3,6 Mcal par kg) assortie à un ratio lysine totale:ED de 3,7, 4,0, 4,3, 4,6 ou 4,9 g par Mcal. L'expérience a duré 28 jours et a débuté le 7 e jour après le sevrage. Elle portait sur quatre porcs par enclos et six enclos par ration pour un total de 240 sujets (27 ± 2 j; 7,5 ± 1,1 kg). Aucune i...

No abstract

The effect of flaxseed processing on the utilization of fatty acids and nitrogen were examined in adult chicken. Two batches (A and B) of flaxseed were processed by autoclaving, pelleting, or microwave roasting. Thirty grams of the ground ingredient was given to fasted Leghorn roosters. The apparent digestibility of total fatty acids of raw flaxseeds A and B were 660 and 490 g kg −1 , respectively. Its improvement (p < 0.05) reached 29% for flaxseed A after three-times repeated pelleting. Similarly, it was 39% (p < 0.05) for flaxseed B after 4 min of microwave roasting. The improvement in the absorption of major individual fatty acids in flaxseed followed the same pattern as that of total fatty acids. The apparent digestibility of linolenic acid in extruded full-fat soybean was much higher (p < 0.05) than that in raw flaxseed A, but not that in processed flaxseed A (p > 0.05). Furthermore, roosters given canola seed had significantly higher true nitrogen utilization (p < 0.05) than those fed raw flaxseed A. This difference was reduced or non-existent (p > 0.05) with processed flaxseed. Proper flaxseed processing effectively increases the utilization of major fatty acids and nitrogen in flaxseed for adult chicken.