The effects of including 3% sunflower hulls (SFH) in the diet on growth performance, nutrient retention (TTAR), and gastrointestinal tract (GIT) traits were studied in chicks from zero to 21 d of age. Four treatments that resulted from the combination of 2 chicken lines (female broilers vs. brown pullets) and 2 levels of SFH (zero vs. 3%) were used. The control diet contained 2,980 kcal AME n /kg, 1.25% digestible Lys, and 8.7% neutral detergent fiber. The experimental diet included 3% SFH at the expense (wt:wt) of the whole diet. Growth performance, TTAR of nutrients, and the AME n of the diet were greater (P = 0.097 to P < 0.001) in broilers than in pullets. In absolute terms, all the organs of the GIT were heavier (P < 0.001) and the small intestine and cecum were longer (P < 0.001) in broilers than in pullets. At 21 d of age, however, the relative weight (% BW) of all the organs of the GIT (P < 0.001) and the relative length (cm/kg BW) of the small intestine and cecum (P < 0.01) were greater in pullets. Gizzard pH (P < 0.001), total short chain fatty acids concentration in the cecum (P = 0.098), and villus height (P < 0.001) and crypt depth (P < 0.05) of the ileum mucosa were higher in broilers. The inclusion of SFH increased (P < 0.05) the AME n content of the diet but did not affect bird performance, moisture content of the excreta, or the concentration and profile of fatty acids in the cecum. Dietary SFH increased gizzard weight and reduced gizzard pH (P < 0.001) at both ages. In conclusion, broilers had better growth performance, nutrient retention, and ileum absorptive capacity than pullets. The inclusion of 3% SFH at the expense of the control diet did not have any negative effect on chick performance and, in fact, increased gizzard weight, reduced gizzard pH, and improved the energy content of the diet.

We investigated the effects of fiber inclusion in the diet on growth performance and digestive traits in pullets from hatching to 17 wk of age. The control diets of the 3 feeding periods (0 to 5 wk, 5 to 10 wk, and 10 to 17 wk) were based on corn and soybean meal and did not include any additional fiber source. The experimental diets included 2 or 4% of cereal straw or sugar beet pulp (SBP) at the expense (wt:wt) of the control diet. From 0 to 5 wk of age, fiber inclusion did not affect pullet performance. From hatch to 17 wk of age, the inclusion of straw had little effect on pullet performance but the inclusion of 4% SBP reduced (ADG) (P < 0.05) and reduced feed conversion ratio (FCR; P < 0.001). Pullets fed straw had greater ADG (P < 0.05) and better energy conversion ratio (P < 0.01) than pullets fed SBP. An increase in fiber from 2 to 4% reduced FCR (P < 0.05). Body weight uniformity was not affected by diet. Fiber inclusion increased the relative weight (% BW) of the gizzard at 5 wk (P = 0.056) and 10 wk (P < 0.01) of age, but no differences were detected between fiber sources. At same ages, the relative length (cm/kg BW) of the pullets (P = 0.058 and P < 0.01, respectively) and tarsus (P = 0.079 and P < 0.05, respectively) was higher in pullets fed SBP than in pullets fed straw. Fiber inclusion, however, did not affect any of these traits at 17 wk of age. In summary, the inclusion of 2% straw at the expense (wt:wt) of the whole diet did not affect pullet performance at 17 wk of age. An increase in the level of straw from 2 to 4% reduced FCR but did not affect ADG. The inclusion of SBP, however, reduced pullet growth, with effects being more pronounced at the higher level.

The influence of source and level of inclusion of raw glycerin (GLYC) in the diet on growth performance, digestive traits, total tract apparent retention (TTAR), and apparent ileal digestibility of nutrients was studied in broilers from 1 to 21 d of age. There was a control diet based on corn and soybean meal and 8 additional diets that formed a 2 × 4 factorial with 2 sources of GLYC and 4 levels of inclusion (2.5, 5.0, 7.5, and 10%). The GLYC used were obtained from the same original batch of soy oil that was dried under different processing conditions and contained 87.5 or 81.6% glycerol, respectively. Type of processing of the GLYC did not affect any of the variables studied except DM and organic matter retention (P < 0.05) that was higher for the 87.5% glycerol diet. From d 1 to 21, feed conversion ratio (FCR) improved linearly (L, P ≤ 0.01) as the GLYC content of the diet increased, but ADG was not affected. On d 21, the relative weight (% BW) of the liver and the digestive tract increased (L, P < 0.01) as the level of GLYC in the diet increased, but lipid concentration in the liver was not affected. The TTAR of DM and organic matter increased quadratically (Q, P < 0.05) and the AME(n) content of the diet increased linearly (L, P < 0.01) with increases in dietary GLYC. Also, the apparent ileal digestibility of DM (L, P < 0.05; Q, P = 0.07) and gross energy (L, P < 0.01) increased as the GLYC content of the diet increased. It is concluded that raw GLYC from the biodiesel industry can be used efficiently, up to 10% of the diet, as a source of energy for broilers from 1 to 21 d of age and that the energy content of well-processed raw GLYC depends primarily on its glycerol content.

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