Biomedical subjects

S Calsamiglia

Publications and source records attributed to S Calsamiglia.

26 records · Page 2Linked to original sources

PubMed2000

Nitrogen metabolism of early lactation cows fed diets with two different levels of protein and different amino acid profiles.

Four multiparous Holstein cows (569+/-122 kg) surgically prepared with indwelling catheters in the mesenteric, portal, and hepatic veins and carotid artery were allocated in a 4 x 4 Latin square to determine the effects of dietary crude protein (CP) level and amino acid (AA) profile on N metabolism during early lactation (from 25 to 65 d in milk). Cows received their diets in two equal meals and were milked twice daily. The dietary treatments were: 18% CP with a high (18H) or a low (18L) quality AA profile, and 15% CP with a high (15H) or a low (15L) quality AA profile. The four diets were similar in net energy for lactation (1.75 NEL Mcal/kg) and contained the same amount of RUP (34% of CP). The quality of the AA profile pertained only to the essential AA (EAA), and was assessed by comparison with the EAA profile of casein and considered the potential contribution of EAA from ruminal bacteria. The 18H and 15H diets were supplemented with 50 and 25 g/d of ruminally protected Met, respectively. After 10 d on treatment, a blood flow marker (p-amino-hippurate) was infused into a mesenteric vein, and arterial, portal, hepatic, and mammary blood samples were obtained at 3, 6, and 12 h after feeding. Dry matter intake was similar across treatments (23.4+/-0.5 kg/d). Amino acid oxidation, and consequent urea production, in the liver were numerically greater with the 18% CP rations, and, as a result, arterial urea concentrations were greatest (P < 0.01) with these rations. The amount of total AA extracted by the mammary gland tended to be greater with the H than with the L diets (21.4 vs. 18.2 mmol/ h, respectively). Milk yield tended to be greater (P = 0.16) with the 18H and 15H diets (47.7 and 46.3 kg/d, respectively) compared with the 18L and 15L diets (45.9 and 44.6 kg/d, respectively). Also, milk CP and casein contents were greatest (P = 0.09) with the H diets compared with the L diets. Milk and plasma urea N were greatest (P < 0.01) with the 18% CP diets. The efficiency of N utilization for milk protein synthesis was greatest (P < 0.09) with the 15% CP diets. It is concluded that milk protein production during early lactation is less susceptible to variations in dietary CP contents than variations in the AA profile of the dietary protein.

Amino Acids↗

PubMed1999

Effects of calcium soaps and rumen undegradable protein on the milk production and composition of dairy ewes.

Forty-eight Manchega dairy ewes were used during a complete lactation in a 2 x 2 factorial design to determine the effects of supplementing diets with fat (calcium soaps of palm oil fatty acids, CSFA) and rumen undegradable protein (RUP) on milk production and composition. Factors tested were amounts of CSFA (0 or 200 g/kg) and RUP (300 or 450 g/kg crude protein) in the concentrate. RUP was altered by adding a mixture of maize gluten meal and blood meal. Lactation was divided into one nursing period (period 1, weeks 1-4), and three milking periods (periods 2-4, weeks 5-8, 9-14 and 15-21). Concentrates were given at 0.8 kg/d during periods 1 and 2, and at 0.6 kg/d in periods 3 and 4. Ewes grazed rotationally in an Italian rye-grass pasture and received a daily supplement of 0.8 kg vetch-oat hay during period 1, and 0.3 kg lucerne hay during periods 2-4. For the whole lactation, supplemental fat markedly increased milk fat content (+23%) and yield (+16%), and decreased milk protein content (-9%). The positive effect of feeding CSFA on milk fat content was more evident at the beginning of lactation; however, its negative effect on milk protein was more pronounced in late lactation. Supplementary RUP had little effect, increasing milk protein content only in period 3, when the crude protein content of pasture was lower. Milk yield and lamb growth were not affected by dietary treatments. The results indicated that CSFA can be useful for increasing the milk fat content of dairy ewes at pasture, which may help farmers to produce milk reaching the minimum requirements of fat content for the cheese industry.

Animal Feed↗

PubMed1997

Alternative techniques for measuring nutrient digestion in ruminants.

Because in vivo measurement of nutrient digestion in the rumen and small intestine requires ruminally and intestinally cannulated animals that are expensive, labor-intensive, and subject to error associated with markers and inherent animal variation, alternative techniques have been developed. Researchers have proposed various in situ or in vitro procedures for estimating ruminal and small intestinal nutrient digestion. This review summarizes these alternative techniques.

Animals↗

PubMed1996

Comparison of nitrogen-15 and purines as microbial markers in continuous culture.

Eight dual-flow continuous-culture fermenters were used in four replicated periods to compare the effects of diet and microbial marker on estimates of N metabolism in continuous culture of ruminal microorganisms. A basal diet was supplemented with urea and tryptone, soybean meal (SBM), lignosulfonate-treated SBM, corn gluten meal, blood meal (BM), hydrolyzed feather meal, fish meal (FM), or meat and bone meal (MBM). Microbial protein flow and protein degradation in fermenters were estimated using purines, purine N, and 15N in bacteria obtained from fermenter flasks or from the effluent. The ratio of purine N to total N in bacteria averaged .083 and was not affected (P > .05) by treatment. Dietary purine content (percentage of DM) ranged from .033 in BM to .084 in FM. Escape of feed purine N (percentage of total purine N flow) averaged 1.7% (SE = 2.9) and was not different (P > .05) among treatments. Bacterial N flows obtained using purines were more variable than estimates obtained using 15N. Bacterial N flows calculated using 15N in bacteria isolated from fermenters were more variable than those obtained using bacteria isolated from the effluent. The use of purines as a microbial marker resulted in lower estimates of protein degradation and smaller differences among treatments compared with use of 15N. Data suggest that escape of feed purine N seems to be a minor factor affecting calculation of bacterial N flow and that the use of 15N in effluent bacteria may be a more accurate procedure when using continuous-culture fermenters.

Animals↗

PubMed1995

A three-step in vitro procedure for estimating intestinal digestion of protein in ruminants.

A three-step in vitro procedure was developed to estimate intestinal digestion of proteins in ruminants. Dacron bags containing feed samples were suspended in the rumen for 16 h. Residue containing 15 mg of N after ruminal exposure was incubated for 1 h in 10 mL of a .1 N HCl solution containing 1 g/L of pepsin. After incubation, pH was neutralized with .5 mL of 1 N NaOH and 13.5 mL of a pH 7.8 phosphate buffer containing 37.5 mg of pancreatin were added to the solution and incubated at 38 degrees C. After a 24-h incubation, 3 mL of a 100% (wt/vol) trichloroacetic acid solution were added to precipitate undigested proteins. Preincubation of samples in the rumen did not affect (P > .05) pepsin-pancreatin digestion of residual CP in soybean meal (SBM), corn gluten meal (CGM), and blood meal (BM) and reduced (P < .05) pepsin-pancreatin digestion of residual CP in hydrolyzed feather meal (HFM), fish meal (FM), and meat and bone meal (MBM) (80 vs 70, 88 vs 81, and 82 vs 56%, respectively, for nonruminal vs ruminal preincubation). Pepsin digestion before pancreatin digestion increased (P < .05) CP digestion of all proteins tested by a mean of 23 percentage units. The pancreatin digestion step was validated using 34 duodenal samples from which small intestinal CP digestion was determined in vivo. The regression equation of in vivo estimates on pancreatin digestion had an r value of .91 (P < .001).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Effects of protein source on nitrogen metabolism in continuous culture and intestinal digestion in vitro.

Eight dual flow continuous culture fermenters were used in four replicated periods to study the effects of protein supplements on ruminal fermentation and CP digestion. A basal diet was supplemented with isonitrogenous amounts of urea and tryptone (control; CTRL), soybean meal (SBM), lignosulfonate-treated SBM (LSBM), corn gluten meal (CGM), blood meal (BM), hydrolyzed feather meal (HFM), fish meal (FM), or meat and bone meal (MBM). Digestion of DM, OM, and carbohydrates was not affected by treatment. Ammonia N concentration was highest (P < .05) for CTRL and lowest (P < .05) for LSBM, CGM, BM, HFM, and FM. Nonammonia N flow was lowest (P < .05) for CTRL. Dietary N flow was lowest (P < .05) for CTRL, intermediate for SBM, and highest (P < .05) for LSBM, CGM, BM, HFM, FM, and MBM. Total N flow, bacterial N flow, and efficiency of microbial protein synthesis were not affected by treatment. Protein degradation was highest (P < .05) for CTRL. Flow of total amino acids (AA) was lowest (P < .05) for CTRL, SBM, and MBM. Diets containing BM provided the largest (P < .05) amounts of essential AA and lysine, and FM provided the largest (P < .05) amounts of methionine in fermenter effluent. Supplementation of diets with proteins low in ruminal degradability increased flows of nonammonia N, dietary N, and total and essential AA and modified the AA profile flowing out of fermenters.

Amino Acids↗

PubMed1995

Effects of ruminal versus duodenal dosing of fish meal on ruminal fermentation and milk composition.

Three midlactation Holstein cows with ruminal and duodenal cannulas were used in a 3 x 3 Latin square design to determine whether ruminal or postruminal alterations in metabolism were responsible for the changes in milk composition that frequently are associated with dietary fish meal. Cows were offered a diet of 60:40 forage to concentrate (aliquots at 6-h intervals) that was supplemented with isonitrogenous amounts of soybean meal (1.3 kg of DM/d) dosed into the rumen or fish meal (1.0 kg DM/d) dosed either into the rumen or into the duodenum. The DMI, ruminal NDF digestion, and flows of total N and microbial N to the duodenum decreased for cows receiving fish meal. Dietary N flow increased when fish meal was dosed into the rumen. Total concentration of ruminal VFA was greater for cows receiving the soybean meal treatment; however, treatment had no effect on the ratio of ruminal acetate plus butyrate to propionate. Milk and FCM yields were unaffected by treatment, but milk fat content decreased, and milk protein content increased when cows were supplemented with fish meal. The difference in mammary arteriovenous glucose difference decreased when cows were dosed with fish meal. Changes in plasma NEFA and triglycerides were small and inconsistent. Results from this experiment suggest that effects of fish meal on milk composition are due to postruminal alterations in metabolism.

Acetates↗

PubMed1992

Effect of fish meal and expeller-processed soybean meal fed to dairy cows receiving bovine somatotropin (sometribove).

Forty-eight multiparous cows were blocked by calving date and milk production and assigned randomly to a TMR formulated to contain 68 or 55% of dietary CP as ruminally degradable CP. Diets contained corn silage, alfalfa haylage, and ground corn. Supplemental CP was soybean meal for the control diet or a combination of soybean meal, expeller-processed soybean meal, and fish meal for the low degradable protein diet. Two 10-wk phases began on d 31 +/- 3 (phase 1) and 110 +/- 7 postpartum [phase 2, all cows received subcutaneous implantations of pelleted (400 mg) bST (sometribove) every 14 d]. Dietary energy, CP, ruminally degradable CP, NDF, and ADF were similar between dietary treatments. Production of FCM increased in response to bST but was not affected by dietary treatment. Cows fed the expeller-processed soybean meal and fish meal TMR produced milk that contained less milk fat in phase 1 and less milk protein content in both phases. The DMI, BW, and body condition scores were not affected by diet. Hematocrit, plasma urea N, albumin, total protein, creatinine, glucose, and serum insulin were similar between dietary treatments. Replacing soybean meal with expeller processed soybean meal and fish meal did not affect ruminal degradation of protein or milk production but decreased milk fat and protein contents.

Animal Feed↗