A.F. Mustafa

Effects of micronization of flaxseed on nutrient disappearance in the gastrointestinal tract of steers

Abstract Two steers fitted with ruminal and duodenal cannulas were used in a randomized complete block design to determine the effects of micronization on ruminal and postruminal and total tract digestibility of protein and amino acids of flaxseed. Micronized flaxseed had lower (P

Effects of the forage to concentrate ratio on B-vitamin concentrations in different ruminal fractions of dairy cows

Two studies were undertaken to verify the effect of the forage to concentrate ratio of the diet on B-vitamin concentrations in ruminal contents. In Study 1, eight primiparous and eight multiparous cows were used in a cross-over design, and concentrations of biotin, folates and vitamin B12 were determined in ruminal fluid and plasma of cows fed a high-forage (HF; 58:42 forage to concentrate ratio; DM basis) or a low-forage (LF; 37:63 forage to concentrate ratio; DM basis) diet. In Study 2, six ruminally cannulated lactating cows were used in a cross-over design to evaluate the effects of forage to concentrate ratio (HF = 60:40; LF = 40:60; DM basis) on concentrations of seven B-vitamins in the particle-free fluid and in both liquid- and solid-associated bacteria. Results showed that B-vitamins were present mainly in the bacterial fractions of the ruminal content, while only limited amounts were found in the surrounding fluid. A change in the forage to concentrate ratio had a greater effect on vitamin conce...

Influence of stearoyl-coenzyme A desaturase 1 genotype and stage of lactation on fatty acid composition of Canadian Jersey cows

Bovine milk contains high proportions of saturated fatty acids (SFA) because of the extensive biohydrogenation of dietary fatty acids in the rumen. Stearoyl-coenzyme A desaturase 1 (SCD1) catalyzes the conversion of C10 to C18 SFA into their monounsaturated (MUFA) counterparts in the mammary glands of ruminant animals; and 2 alleles (A and V) have previously been identified at the SCD1 locus. Genotypes at this locus were identified and fatty acid contents of milk were measured for 525 Canadian Jersey cows. Association analysis indicated that allele A is positively associated with higher C10 (C10I), C12 (C12I) and C14 (C14I) indices and, consequently, with greater contents of C10:1 and C12:1, but not C14:1, relative to allele V. Allele A was also positively associated with increased 305-d milk and protein yields. Allele A, however, had no influence on C16 (C16I), C18 (C18I), or conjugated linoleic acid indices (CLAI) compared with the V allele. Stage of lactation had an influence on desaturase indices and consequently on the MUFA contents of milk fat. The indices C10I, C12I, C14I, and CLAI increased from early to mid lactation as did their respective MUFA. Genetic selection for increased unsaturation of the hypercholesterolemic fatty acids in milk fat is feasible and may be accompanied by increased lactation milk and protein yields.

Characteristics and in situ degradability of whole crop faba bean, pea, and soybean silages

The objective of this study was to determine the ensiling characteristics and ruminal nutrient degradabilities of faba bean (FS, Vicia faba L.), soybean (SS, Glycine max (L.) Merr.) and pea (PS, Pisum sativum L.) silages. Forages were harvested between the beginning- and full-seed stages and ensiled in mini-silos for 0, 2, 4, 16, and 45 d. Two lactating Holstein cows fitted with ruminal fistulae were used to determine ruminal nutrient degradabilities. Results showed that all silages went through a rapid fermentation as indicated by rapid decline in pH and sharp increase in lactic acid concentration within the first 2 d of ensiling. Extensive proteolysis took place between day 0 and day 4 post-ensiling as indicated by a significant reduction in true protein (TP) and a significant increase in non-protein nitrogen (NPN). During the 45 d of ensiling, TP decreased (P < 0.05) by 26, 31, and 45% while NPN increased (P < 0.05) by 82, 54, and 47% for FS, SS, and PS, respectively. Chemical analysis showed that the ...

Stearoyl-CoA desaturase 1 genotype and stage of lactation influences milk fatty acid composition of Canadian Holstein cows.

Single nucleotide polymorphisms in the coding region of the bovine stearoyl-CoA desaturase 1 gene have been predicted to result in p.293A (alanine at amino acid 293) and p.293V (valine at amino acid 293) alleles at the stearoyl-CoA desaturase1 locus. The objectives of this study were to evaluate the extent to which genotypes at the stearoyl-CoA desaturase 1 locus and stage of lactation influence milk fatty acid composition in Canadian Holstein cows. Cows with the p.293AA genotype had higher C10 index, C12 index and C14 index and higher concentrations of C10:1 (10 carbon fatty acid with one double bond), C12:1 (12 carbon fatty acid with one double bond) and myristoleic acid (C14:1) compared with the p.293AV or p.293VV cows. Cows had higher C18 index and total index, and lower C10 index, C12 index, C14 index and CLA index during early lactation compared with the subsequent lactation stages. Early lactation was also characterized by higher concentrations of oleic acid (C18:1 cis-9), vaccenic acid (C18:1 trans-11), linoleic acid (C18:2), monounsaturated fatty acids and total polyunsaturated fatty acids, and lower concentrations of capric acid (C10:0), C10:1, lauric acid (C12:0), C12:1, myristic acid (C14:0), myristoleic acid (C14:1), palmitic acid (C16:0) and total saturated fatty acids compared with the subsequent lactation stages. Neither the stearoyl-CoA desaturase 1 genotype nor the stage of lactation had an influence on conjugated linoleic acid concentrations in milk.

Comparison of corn-based and Canadian pearl millet-based diets on performance, digestibility, villus morphology, and digestive microbial populations in broiler chickens

A study was undertaken to examine the effects of partially or totally replacing corn with pearl millet in broiler diets on growth performance, jejunal digesta viscosity, and histomorphological parameters, ileal CP digestibility, and cecal microbial populations. Two hundred 1-d-old male Ross 508 broilers were randomly assigned to 1 of 5 isonitrogenous and isocaloric dietary treatments (8 cage replicates; 5 birds/cage) and grown over a 42-d experimental period. Dietary treatments included a standard corn-soybean meal diet and one in which the total amount of grain (corn + pearl millet) consisted of 25, 50, 75, or 100% pearl millet. All diets contained chromic oxide (0.4%) as an indigestible marker. Body weight and feed intake were recorded weekly throughout 42 d. At d 14, 28, and 42, 8 birds/treatment (1 bird/cage) were killed for sample collection and analysis. In comparison with corn, pearl millet grain contained higher CP (14.48 vs. 7.35%, on a DM basis) but slightly lower ME (3,093 vs. 3,355 kcal/kg, on a DM basis). Total replacement of corn by pearl millet significantly (P < 0.05) improved BW and feed conversion. Moreover, in comparison with the standard diet, feeding broilers pearl millet-based diets had no detrimental effects on digesta viscosity, villus height, villus width, and villus surface area of the jejunum. Ileal CP digestibility and cecal concentrations of Escherichia coli, lactobacilli, and bifidobacteria were also similar between birds fed corn and pearl millet. It was concluded that substituting corn for pearl millet in broiler diets can improve production responses without causing any adverse effects on nutrient digestibility or bird health.

Effects of extrusion of flaxseed on ruminal and postruminal nutrient digestibilities

A study was conducted to determine the effects of extrusion on ruminal, post-ruminal and whole tract digestibility of flaxseed. Extrusion was performed at 155°C with a residence time of 43 s. Two non-lactating Holstein cows fitted with ruminal and duodenal cannulas were used in a randomized complete block design. Results showed that extruded flaxseed had higher (P < 0.05) in situ soluble and lower (P < 0.05) slowly degradable DM and CP fractions than unheated flaxseed. Extrusion increased (P < 0.05) ruminal DM and CP degradability of flaxseed by 7 and 13%, respectively. Ruminal undegraded DM, CP and NDF were all lower (P < 0.05) for extruded flaxseed than for unheated flaxseed. Extrusion increased (P < 0.05) ruminal degradability and reduced (P < 0.05) post-ruminal availability of most amino acids of flaxseed. Whole tract digestibility of DM, CP, NDF and amino acids were higher (P < 0.05) for extruded than for unheated flaxseed. It was concluded that extrusion under the conditions used in the present experiment increases ruminal and whole tract nutrient degradabilities of flaxseed and therefore was ineffective in increasing the post-ruminal supply of amino acids from flaxseed.

Effect of feeding extruded flaxseed with different forage:concentrate ratios on the performance of dairy cows

Twenty Holstein cows were used in a Latin square design experiment with a 2×2 factorial arrangement to determine the effects of extruded flaxseed (EF) supplementation with 2 different forage to concentrate ratios on the performance of dairy cows. Extruded flaxseed diets contained 9% (dry matter basis) EF product which consisted of 75% EF and 25% ground alfalfa meal. Four lactating Holsteins cows fitted with rumen fistulae were used to determine the effects of dietary treatments on ruminal fermentation. Intakes of dry matter and crude protein were not influenced by dietary treatments. However, neutral detergent fiber intake was greater for the high-forage (8.4 kg/d) than the low-forage (7.8 kg/d) diet. Milk yield (average 40.2 kg/d) was similar for all dietary treatments. However, cows fed the high-forage diets produced milk with higher fat (3.76 vs. 2.97%) and total solids (12.58 vs. 11.95%) concentrations, but lower protein (3.19 vs. 3.33%) and lactose (4.66 vs. 4.72%) contents. Ruminal pH and total volatile fatty acid concentration were not affected by dietary treatments. However, feeding high forage relative to low forage diets increased molar proportion of acetate but decreased that of propionate. Ruminal NH3-N was reduced by feeding high forage relative to low forage diets. Milk fatty acid composition was altered by both forage level and EF supplementation. Feeding diets containing EF or low forage reduced the concentrations of saturated fatty acids and increased those of mono-unsaturated fatty acids. Concentrations of poly-unsaturated fatty acids were increased by feeding EF or low-forage diets. Extruded flaxseed supplementation increased milk fat α-linolenic acid content by 100% and conjugated linoleic acid by 54%. It was concluded that differences in animal performance and ruminal fermentation observed in this study were mostly due to differences in forage to concentrate ratio. However, EF supplementation caused most of the differences observed in milk fatty acid composition.

Nutritional value of feed grade chickpeas for ruminants and pigs

The feeding value of feed grade chickpeas (Kabuli and Desi type) for ruminants and pigs was determined in two studies. Two ruminally fistulated cows were used in the first study to determine the effects of moist heat treatment (127 °C for 10 min) on the ruminal protein degradability of feed grade chickpeas. Heat treatment reduced (P < 0.05) soluble crude protein and increased (P < 0.05) the amount of crude protein associated with neutral detergent fibre for both types of chickpeas. Ruminal degradability of crude protein for Kabuli and Desi chickpeas was reduced by 39 and 33% (P < 0.05) respectively as a result of heating. In the second study, 64 crossbred pigs were each assigned to one of four dietary treatments in a factorial (4 treatments × 2 sexes) design experiment. The experimental barley/wheat-based diets were supplemented with either soybean meal (control), Kabuli chickpeas (300 g kg−1), Desi chickpeas (300 g kg−1) or field peas (300 g kg−1). Dry matter and gross energy digestibility coefficients, determined using the indicator method, were lower (P < 0.05) for the Desi- than for the Kabuli-supplemented diet. However, no differences were observed in dry matter or gross energy digestibility between the Kabuli chickpea-supplemented diet and the control or the field pea-supplemented diet. Diets supplemented with chickpeas or field peas had a lower (P < 0.05) crude protein digestibility than the control diet. Pigs fed either of the chickpea-supplemented diets during the growing phase gained less (P < 0.05) than pigs fed the control diet. However, during the finishing phase and over the entire experiment, dietary treatment had no effect on pig performance. There were no significant differences in carcass traits between pigs fed any of the four diets. It was concluded that moist heat treatment is an effective method to increase the rumen escape protein value of chickpeas and that the inclusion of feed grade Kabuli or Desi chickpeas in finishing diets up 300 g kg−1 had no detrimental effects on pig performance. © 2000 Society of Chemical Industry

Feeding micronized and extruded flaxseed to dairy cows: Effects on digestion and ruminal biohydrogenation of long-chain fatty acids

Four lactating Holstein cows fitted with ruminal and duodenal cannulae were used in a 4 × 4 Latin square study to determine the effects of feeding micronized and extruded flaxseed on ruminal biohydrogenation (BH) and digestibility of fatty acids (FA) in the gastrointestinal tract. Four diets were formulated: a control diet with no flaxseed (C); a raw flaxseed diet (RF); a micronized flaxseed diet (MF); and an extruded flaxseed diet (EF). Flaxseed diets contained 126 g kg-1 flaxseed (dry matter basis). Experimental periods (n = 4) consisted of 21 d of diet adaptation and 7 d of data collection. Flaxseed supplementation increased (P < 0.05) intake of individual long-chain FA, reduced (P < 0.05) ruminal BH of total unsaturated C18, and increased (P < 0.05) duodenal flow of individual long-chain FA except for C18:2. Feeding flaxseed increased (P < 0.05) post-ruminal digestibility of C18:1, C18:2, and C18:3 and total tract digestibility of C16:0, C18:2, C18:3, and of total long-chain FA. Heat treatment had no ...