Acid Detergent Fiber Levels Research Articles

Body Composition in Suckling Rabbits1

Two hundred and one lots of suckling rabbits (103 of the Spanish Giant and 98 of the New Zealand breeds) were slaughtered at 0, 20, 25, 30 and 35 days of age and the energy, nitrogen, fat, water and ash contents of their bodies were determined. The rabbits suckled their mothers for 20 days. Afterwards they were offered four different starter feeds having two levels of acid detergent fiber (7 and 10%) and two levels of crude protein (17 and 20%). Weight was a good predictor of body composition, except for fat content. Age influenced body composition and was highly correlated to weight. This influence was significant (P<.05) for every body constituent, except ash, at all ages. New Zealand suckling rabbits had higher total fat content (P<.001), total energy (P<.01) , and lower water content (P<.01), than Spanish Giant ones of equal weight and age. Neither sex nor starter fed composition influenced body composition. Prediction of body composition based on fat, water, or protein contents was not better than that based on body weight.

CHEMICAL COMPOSITION OF AQUATIC MACROPHYTES I. INVESTIGATION OF ORGANIC CONSTITUENTS AND NUTRITIONAL POTENTIAL

Chemical analyses were conducted on unwashed samples of four aquatic plant species harvested at three progressive dates during 1974. All species showed an extremely high ash content. The ash content increased in Potamogeton spp. with progress in the harvesting time and varied only slightly in Cladophora glomerata. Myriophyllum spicatum and Vallisneria americana, harvested in September, were second growth, which was reflected in the much lower ash and considerably higher organic nutrient levels. The neutral-detergent fiber (NDF) level tended to be higher in all species for samples harvested in September. Acid-detergent fiber (ADF) was also higher during the same month except in Potamogeton spp. With the exception of Potamogeton spp., the level of acid-detergent lignin (ADL) was similar in all species at the different dates. Both NDF and ADF values were inflated because of unavoidable contamination with mineral matter. A further experiment with washed and unwashed plant samples harvested the following year showed that washing decreased the ash content markedly, in most cases with a concomitant increase in proximate constituents and gross energy values. All species, either washed or unwashed, were very low in dry matter (5–20%); the NDF and ADF levels for most plants were similar to those of alfalfa, while ADL content was relatively low. Results indicated that aquatic macrophytes would have nutritive value similar to alfalfa; however, their high ash and low dry matter contents would necessitate quality control and additional processing for possible use as feedstuffs.

Laboratory and in Vivo Evaluation of the Nutritive Value of NaOH-Treated Wheat Straw

Three laboratory trials were conducted to determine the effects of type of chemical, concentration of chemical, and concentration and duration of sodium hydroxide (NaOH) treatment upon the nutritive value of ground wheat straw (WS). NaOH, potassium hydroxide and ammonium hydroxide improved in vitro dry matter digestibility (IVDMD) of the straw at either the 2 or 4% (W/W) levels. In vitro organic matter digestibility (IVOMD) of WS increased (P<.01) while levels of acid detergent fiber (ADF) (P<01), acid detergent lignin (P<.05), cell wall constituents (P<.01) and hemicellu-lose (P<.05) decreased with increasing concentrations of NaOH (0 to 16% W/W) per dry weight of WS. Concentrations of crude protein (P<05), ash (P<05) and ADF (P<01) increased while hemicellulose decreased (P<.01) as duration of chemical treatment increased (0–56 days). An interaction (P<.01) between NaOH concentration and duration of treatment was detected upon IVOMD. In a steer feeding trial, diets containing either 50% untreated or NaOH-treated WS were evaluated. In addition, three levels of dietary urea (0, 1 or 2%) were evaluated with the NaOH-treated WS. Average daily gain (ADG) and daily dry matter (DM) intake were increased (P<.05) by treating ground WS with NaOH. However, the addition of urea to the NaOH-treated WS diets decreased (P<05) ADG and DM intake and increased (P<.05) feed/gain ratio. Carcass parameters were generally not affected by treatment. In digestion and nitrogen balance trials evaluating the same diets, the apparent DM and crude fiber digestibilities were increased (P<05) by treatment of WS with NaOH. Percent urinary N excretion was increased (P<.05), and percent N retention tended to be lower with the yrea-containing diets.

Predicting dry matter digestibility from acid detergent fibre levels in grasses as affected by a pretreatment with neutral detergent

AbstractAcid detergent fibre was determined on 50 grass samples of known in vivo dry matter digestibility with and without a preliminary extraction with neutral detergent. Pretreatment with neutral detergent reduced the mean yield of acid detergent fibre from 41.5 to 36.8%. This decrease in acid detergent fibre was mainly due to a reduction in the level of ash which accounted for 57% of the difference in fibre level.The error in predicting dry matter digestibility of all feeds from acid detergent fibre was ±3.5 digestibility units and was increased to ±3.8 units following neutral detergent pretreatment. When acid detergent fibre was expressed on an ash‐free basis the corresponding residual standard deviations were ±4.4 and ±4.5 units, respectively. It was concluded that a pretreatment with neutral detergent or expressing results on an ash‐free basis did not improve the accuracy in predicting dry matter digestibility from acid detergent fibre.