Intake and digestion of leaves of Quercus calliprinos, Pistacia lentiscus, and Ceratonia siliqua, with and without supplementation of various amounts of polyethylene glycol (PEG), were examined. The tannin contents in these species exerted a substantial negative effect on feed intake and digestion. The effects were species specific and related to tannin content. Once-daily Supplementation with PEG efficiently neutralized the negative effects of tannins. The amount of PEG needed to produce a maximal increase in feed intake was lower than the amount required to produce a maximal increase in digestibility. The intake of digestible crude protein and metabolizable energy was raised in PEGsupplemented animals from a submaintenance level to levels considerably exceeding the maintenance requirement of goats. The response was related to the tannin content of the plant.

1. Body weight and the weight of the digestive organs and activities of some digestive enzymes were determined from hatching to 23 d of age. 2. Relative daily growth rate peaked at 11 d of age (22% gain/d) and then decreased gradually. 3. The vitelline residue was decreased rapidly from 4.6 g at hatching to negligible values from 4 d of age. 4. Maximal allometric growth of the pancreas and small intestine was 4-fold and that of liver 2-fold greater than that of the body. 5. Activities (units/kg body weight) of the digestive enzymes measured in the pancreas and intestinal contents increased with age. In the pancreas maximal values were attained on day 8 for amylase and lipase and 11 for trypsin and chymotrypsin. In the small intestine maxima were attained on day 4 for lipase, 11 for trypsin and chymotrypsin and 17 for amylase. 6. The development of secretion of digestive enzymes in the post-hatched chick could be a limiting factor in digestion and subsequently in food intake and growth.

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Diets were prepared with corn, wheat, or sorghum ground in a hammer mill and sieved to obtain coarse, medium, and fine particle size fractions. Their effect on broiler performance from hatch to 7 d and from 7 to 21 d of age was studied. The effect of particle size on the size and pH of the gastrointestinal organs was also determined. The three textures obtained for each grain were uniform in geometric mean diameter (GMD) and geometric standard deviation (GSD). Grain by texture interactions were not significant. Independent of grain source, the best performance was obtained with diets prepared from the medium texture. In these diets, the GMD of the grains varied from 1.13 to 1.23 mm and the GSD from 1.19 to 1.35. The fine fraction (GMD .57 to .67 mm) resulted in the lowest performance and that resulting from the coarse fraction (GMD 2.01 to 2.10 mm) was intermediate. At 7 and 21 d of age, gizzard weight and content were positively related to particle size. At the age of 21 d, duodenum weight and content was highest in chicks fed the fine diets. The pH of the gizzard content decreased with increasing grain particle size, whereas that of the small intestinal content increased. Some grain effects were also observed on the gastrointestinal tract. Gizzard weight was greatest in the cornfed birds. Wheat-fed chicks had the heavier intestines and contents. After overnight feed deprivation, feed consumption by 7-d-old chicks was related to the particle size during the first 2 h of refeeding, with greater intake of medium and coarse grains.