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The influence of the screen size used to grind the main cereal of the diet on egg production, gastrointestinal tract (GIT) development, and body measurements was studied in hens from 17 to 49 wk of age. Diets formed a 2 × 5 factorial with 2 main cereals (corn vs. barley) and 5 screen sizes of the cereal (4, 6, 8, 10, and 12 mm). Each treatment was replicated 5 times. No interactions between main cereal and screen size were observed for any of the traits studied. Cereal type and screen size did not affect feed intake, egg production, BW gain, or quality traits of the eggs. Eggs tended to be larger (P = 0.092) in hens fed the barley diet than in hens fed the corn diet. Also, feed conversion ratio tended to increase (P = 0.081) when the cereal of the diet was ground with a 4-mm screen as compared with the average of the other diets. At 49 wk of age, the relative weight (% BW) of the GIT and gizzard was greater (P < 0.05) in hens fed barley than in hens fed corn. An increase in the screen size increased linearly the relative weight of the GIT (P = 0.089), gizzard (P < 0.01), and liver (P = 0.056). None of the other GIT traits or body measurements was affected by the main cereal or the screen size. In summary, barley can substitute up to 45% of the corn in diets for laying hens without any adverse effect on egg production. Therefore, the use of one or other cereal will depend on their relative cost. An increase in screen size improved gizzard development but had little effect on hen productivity. Within the range studied, the size of the screen used for grinding the cereal had little effect on hen productivity, although the use of a 4-mm screen might increase feed conversion ratio and gizzard development.

The effects of including soy protein concentrate (SPC) and soybean meal (SBM) of different origins in the diet on growth performance and nutrient digestibility of weanling pigs were studied in 2 experiments. In both experiments, pigs received in phase I (21–49 d of age) one of five diets that differed in the soy protein source used. Two diets were based on SPC from USA or Brazil (BRA) origin and the other three diets were based on SBM from USA, BRA or Argentina (ARG) origin. In phase II (49 to 57 d of age), all pigs received a common maize-SBM diet. Pre-planned orthogonal comparisons (SPC vs. SBM; USA vs. BRA SPC; and USA vs. BRA vs. ARG SBM) were conducted to detect differences among soy treatments. In experiment 1, growth performance was similar for piglets fed diets containing SPC than for piglets fed diets containing SBM. In phase I (P = 0.067) and cumulatively (P = 0.082), post-weaning diarrhea (PWD) was lower in pigs fed SPC than in pigs fed SBM. The inclusion of USA meal in the diet improved ADG (P

The influence of feed form and energy content of the rearing phase diets on hen productivity,gastrointestinal tract (GIT) traits and body measurements was studied in brown-egg layinghens fed diets differing in energy concentration from 17 to 46 wk of age. The experimentwas completely randomized with 12 treatments arranged as a (2 × 3) × 2 factorial with twofeed forms (mash vs. crumbles) and three AMEnconcentrations of the rearing phase diets(low, medium and high) and two AMEnconcentrations (11.10 vs. 11.52 MJ/kg) of the layingphase diets. The AMEnof the rearing phase diets differed in 0.42 MJ/kg in all three periods(1?5 wk, 5?10 wk and 10?17 wk of age). Hen productivity was determined from 17 to 46wk and GIT and body traits were measured at 46 wk of age. The characteristics of the rearingphase diets did not affect any of the production, GIT traits or body measurements studiedduring the laying phase, except body weight gain (BWG) from 17 to 46 wk of age that washigher (P < 0.01) in hens that were fed mash during the rearing phase than in hens thatwere fed crumbles. An increase in the energy content of the laying phase diet from 11.10to 11.52 MJ AMEn/kg reduced feed intake (P < 0.001) and improved feed conversion ratio(P < 0.001) from 17 to 46 wk and reduced gizzard contents (P < 0.01) at 46 wk of age butdid not affect any of the other production trait studied. The characteristics of the rearingand laying hen diets did not affect any of the GIT traits or body measurements at 46 wk ofage. Body weight of the hens was positively (P < 0.001) related with body length, body massindex, tarsus length and tarsus diameter at this age. The data indicate that neither feed formnor energy concentration of the rearing phase diets affected subsequent hen performance.An increase in the AMEncontent of the layer diet from 11.10 to 11.52 MJ/kg decreased feedintake and improved feed conversion ratio but did not affect hen production or egg quality.

This research studied the effects of additional fiber in the rearing phase diets on egg production, gastrointestinal tract (GIT) traits, and body measurements of brown egg-laying hens fed diets varying in energy concentration from 17 to 46 wk of age. The experiment was completely randomized with 10 treatments arranged as a 5 × 2 factorial with 5 rearing phase diets and 2 laying phase diets. During the rearing phase, treatments consisted of a control diet based on cereals and soybean meal and 4 additional diets with a combination of 2 fiber sources (cereal straw and sugar beet pulp, SBP) at 2 levels (2 and 4%). During the laying phase, diets differed in energy content (2,650 vs. 2,750 kcal AMEn/kg) but had the same amino acid content per unit of energy. The rearing diet did not affect any production trait except egg production that was lower in birds fed SBP than in birds fed straw (91.6 and 94.1%, respectively; P < 0.05). Laying hens fed the high energy diet had lower feed intake (P < 0.001), better feed conversion (P < 0.01), and greater BW gain (P < 0.05) than hens fed the low energy diet but egg production and egg weight were not affected. At 46 wk of age, none of the GIT traits was affected by previous dietary treatment. At this age, hen BW was positively related with body length (r = 0.500; P < 0.01), tarsus length (r = 0.758; P < 0.001), and body mass index (r = 0.762; P < 0.001) but no effects of type of diet on these traits were detected. In summary, the inclusion of up to 4% of a fiber source in the rearing diets did not affect GIT development of the hens but SBP reduced egg production. An increase in the energy content of the laying phase diet reduced ADFI and improved feed efficiency but did not affect any of the other traits studied.

Two experiments were conducted to study the effects of inclusion of additional fiber in the Phase I diet on growth performance and nutrient digestibility in piglets reared under "optimal" or "poor" hygienic conditions. In both experiments, the design was completely randomized with a control diet that contained 2.2% crude fiber and 8 additional isonutritive diets that included 2.5 or 5.0% of sugar beet pulp (SBP), straw, oat hulls (OH), or wheat middlings (WHM). Preplanned polynomial contrasts were used to study the effects of 1) fiber inclusion (control diet vs. average of the 8 fiber-containing diets), 2) source of fiber, 3) level of fiber, and 4) interaction between source and level of fiber. In Exp. 1 (clean barn), fiber inclusion increased ( < 0.01) the incidence of postweaning diarrhea (PWD) and reduced ( < 0.05) feed efficiency and apparent total tract digestibility (ATTD) of all nutrients except that of CP, which was not affected. Piglet performance was not affected by source or level of dietary fiber. The ATTD of all nutrients decreased ( < 0.05) as the level of fiber increased and was lower in pigs fed straw or OH than in pigs fed SBP or WHM. The apparent ileal digestibility of GE and DM decreased ( < 0.05) with fiber inclusion, a reduction that was more pronounced ( < 0.05) with straw or SBP than with OH inclusion, with WHM inclusion being intermediate. Fiber inclusion did not affect villous height to crypt depth ratio of the ileum mucosa. The inclusion of 5% of a fiber source increased and counts in the cecum ( < 0.001) but the to ratio was not affected. In Exp. 2 (dirty barn), fiber inclusion did not affect piglet performance but tended to increase PWD ( = 0.07). Also, fiber inclusion reduced ( < 0.05) the ATTD of all dietary components except that of CP, which was not affected. Source and level of fiber did not affect ATTD of nutrients except for DM, which was greater for pigs fed SBP than for pigs fed straw ( < 0.05). In conclusion, in the current research, pigs reared under optimal hygienic conditions had lower incidence of PWD, better growth performance, and greater DM and GE digestibility than pigs reared under poor hygienic conditions. An excess of dietary fiber was more detrimental for all these traits in piglets reared under optimal hygienic conditions. The effects of the source and level of fiber on piglet performance was limited in the 2 experiments.

The influence of CP content and ingredient complexity, feed form, and duration of feeding of the Phase I diets on growth performance and total tract apparent digestibility (TTAD) of energy and nutrients was studied in Iberian pigs weaned at 28 d of age. There were 12 dietary treatments with 2 type of feeds (high-quality, HQ; and low-quality, LQ), 2 feed forms (pellets vs. mash), and 3 durations (7, 14, and 21 d) of supply of the Phase I diets. From d 7, 14, or 21 (depending on treatment) to d 35, all pigs received a common diet in mash form. Each treatment was replicated 3 times (6 pigs/pen). For the entire experiment, ADG (P0.05) and ADFI (P0.01) were less with the HQ than the LQ Phase I diets, but G:F was not affected. Pelleting of the Phase I diets did not affect ADG but improved G:F (P0.01). Feeding the Phase I diets from d 0 to 21 improved G:F (P0.05) but decreased ADG (P0.01) as compared with 7 or 14 d of feeding. Postweaning diarrhea (PWD) tended to be greater (P = 0.06) for pigs fed the HQ diets than pigs fed the LQ diets and pigs fed pellets than those fed mash (P0.001). Also, PWD was greater for pigs fed the Phase I diet for 14 or 21 d than those fed the diet for 7 d (P0.01). From d 0 to 21, ADG and G:F were not affected (P0.10) by feed quality, but feeding pellets or increasing the duration of feeding the Phase I diets improved G:F (P0.01). Also, in this period, PWD was greater with pellets than with mash and for pigs fed the Phase I diets for 14 or 21 d than for pigs fed the diet for only 7 d (P0.01). From d 21 to 35, pigs previously fed the LQ diet had greater ADG than pigs fed the HQ Phase I diets (P0.001). Also, pigs fed the Phase I diets for 21 d had decreased ADG (P0.05) and ADFI (P0.001) and reduced G:F (P0.05) than pigs fed these diets for 7 or 14 d. Organic matter digestibility was greater for pigs fed the HQ Phase I diets than pigs fed the LQ Phase I diets (P0.05). Pelleting improved TTAD of all nutrients (P0.01). It is concluded that HQ Phase I diets increased TTAD of nutrients but not feed efficiency of Iberian pigs from d 0 to 35. Also, pelleting improved energy and nutrient digestibility and feed efficiency. Increasing the duration of supply of the Phase I diets from 7 to 21 d improved feed efficiency but reduced ADG. Therefore, the use of LQ Phase I diets in pellet form for no more than 7 d after weaning is recommended in Iberian pigs.