Acute phase response in lactating dairy cows during hyperinsulinemic hypoglycaemic and hyperinsulinemic euglycaemic clamps and after intramammary LPS challenge.

The link between energy availability, turnover of energy substrates and the onset of inflammation in dairy cows is complex and poorly investigated. To clarify this, plasma inflammatory variables were measured in mid-lactating dairy cows allocated to three groups: hyperinsulinemic hypoglycaemic clamp, induced by insulin infusion (HypoG, n = 5); hyperinsulinemic euglycaemic clamp, induced by insulin and glucose infusion (EuG; n = 6); control, receiving a saline solution infusion (NaCl; n = 6). At 48 h after the start of i.v. infusions, two udder quarters per cow were challenged with 200 µg of E. coli lipopolysaccharide (LPS). Individual blood samples were taken before clamps, before LPS challenge (i.e. 48 h after clamps) and 6.5 h after. At 48 h, positive acute phase proteins (posAPP) did not differ among groups, whereas albumin and cholesterol (index of lipoproteins), negative APP (negAPP), were lower (p < 0.05) in EuG compared to NaCl and HypoG. The concentration of IL-6 was greater in EuG (p < 0.05) but only vs. HypoG. At 6.5 h following LPS challenge, IL-6 increased in the NaCl and EuG clamps (p < 0.05), while TNF-α increased (p < 0.05) in the EuG only. Among the posAPP, haptoglobin markedly increased in EuG (p < 0.05), but not in NaCl (p = 0.76) and in HypoG; ceruloplasmin tended to decline during LPS challenge, the reduction was significant when all animals were considered (p < 0.05). Conversely, all the negAPP showed a marked reduction 6.5 h after LPS challenge in the three groups. In conclusion, EuG caused an inflammatory status after 48-h infusion (i.e. decrease of negAPP) and induced a quicker acute phase response (e.g. marked rise of TNF-α, IL-6) after the intramammary LPS challenge. These data suggest that the simultaneous high availability of glucose and insulin at the tissue-level makes dairy cows more susceptible to inflammatory events. In contrast, HypoG seems to attenuate the inflammatory response.

Television viewing duration and blood pressure among 18-74-year-old adults. The French nutrition and health survey (ENNS, 2006-2007).

OBJECTIVES: To describe Blood Pressure (BP) according to the time spent viewing television and examine whether the associations between television viewing and systolic and diastolic BP differed depending on sex, age and BMI. DESIGN: The French health and nutrition survey (ENNS) was conducted in 2006-2007 on a multistage stratified random sample of 18-74-year-old adults. METHODS: Systolic (SBP) and diastolic BP (DBP) were assessed using three measurements. Among subjects without BP-lowering drugs and lifestyle measures, adjusted means of SBP and DBP were estimated for each television viewing category (<3h and ≥3h). RESULTS: Among 2050 ENNS participants, 81.2% declared neither drug medication nor lifestyle change to lower BP. In women without BP-lowering measure, viewing television 3h/day or more increased significantly SBP and DBP adjusted means (+2mmHg) compared to women who spent less than 3h/day in front of the television. These associations were stronger in obese or 35-54-year-old women. In men, no relationship between DBP and television-viewing has been observed. Though, SBP was positively associated with television-viewing in non-overweight, 18-29 or 55-74 year-old men. CONCLUSIONS: These results show that the association between television viewing duration and BP must be evaluated differently between gender, age group and BMI category.

Body-weight perception and related preoccupations in a large national sample of adolescents.

OBJECTIVES: This study aimed to investigate the association between body-weight (BW) perception, weight preoccupation and behaviour, including weight control practices and compulsive over-eating episodes, across gender and actual BW classes. DESIGN: This study used a cross-sectional observational study. PARTICIPANTS: A large, nationally representative sample of 6404 ninth-grade French adolescents was randomly selected from schools throughout France. METHODS: Weight and height were measured, and BW preoccupation, BW control practices and compulsive over-eating were self-reported using standardized questionnaires. RESULTS: Nearly one-third of adolescents misperceived their BW. Misperception was more frequent among girls than boys (42.2% vs. 27.3%, P < 0.01). Underestimation of BW among overweight adolescents, like BW overestimation among underweight adolescents, was associated with less preoccupation with weight and fewer weight control practices than accurate perception of BW. Normal weight adolescents who overestimated their BW were more likely to declare weight preoccupations (ORa = 8.66 [6.67-11.25]), dieting (ORa = 4.81 [3.68-6.27]) and recurrent compulsive over-eating episodes (ORa = 2.36 [1.72-3.23]) compared with their counterparts who correctly estimated their BW. CONCLUSION: Our study underlines the role of these associations in each category of actual BW (underweight, normal weight and overweight) in a large national sample.

Metabolic syndrome and socioeconomic status in France: The French Nutrition and Health Survey (ENNS, 2006-2007).

OBJECTIVES: The main objective was to estimate, in France, the prevalence of metabolic syndrome (MetS) and to investigate the association between socioeconomic position and MetS. METHODS: The French National Nutrition and Health Survey (ENNS) cross-sectional national multistage sampling was carried out in 2006-2007. Data collection included waist circumference and blood pressure measurements, blood sample and sociodemographic and medication information. The prevalence of MetS was assessed using several definitions, including Joint Interim Statement (JIS). Association with sociodemographic covariates was assessed using logistic regression models. RESULTS: Among the 1,856 participants 18-74 years of age, MetS prevalence was found to vary from 14.6 % (National Cholesterol Education Program definition) to 21.1 % (JIS), with no difference between genders. After adjustment, risk of MetS increased with age in both men and women. In women, MetS risk was inversely associated with education level. Risk of MetS was higher in men born outside France than in French-born males. CONCLUSIONS: MetS prevalence appeared to be lower in France than in most industrialised countries. The promoting of public health measures to reduce MetS, for example, lifestyle changes, is of utmost importance, particularly among less favourable socioeconomic categories and among migrants.

Long-term elevation of ß-hydroxybutyrate in dairy cows through infusion: effects on feed intake, milk production, and metabolism.

Elevation of ketone bodies in dairy cows frequently occurs in early lactation, usually concomitantly with a lack of energy and glucose. The objective of this study was to induce an elevated plasma ß-hydroxybutyrate (BHBA) concentration over 48 h in mid-lactating dairy cows (i.e., during a period of positive energy balance and normal glucose plasma concentrations). Effects of BHBA infusion on feed intake, metabolism, and performance were investigated. Thirteen cows were randomly assigned to 1 of 2 infusion groups, including an intravenous infusion with Na-dl-ß-OH-butyrate (1.7 mol/L) to achieve a plasma concentration of 1.5 to 2.0 mmol/L of BHBA (HyperB; n=5), or an infusion of 0.9% saline solution (control; n=8). Blood was sampled before and hourly during the 48 h of infusion. In the liver, mRNA transcripts related to gluconeogenesis (pyruvate carboxylase, glucose 6-phosphatase, mitochondrial phosphoenolpyruvate carboxykinase), phosphofructokinase, pyruvate dehydrogenase complex, and fatty acid synthesis (acetyl-coenzyme A carboxylase, fatty acid synthase) were measured by real-time PCR. Glyceraldehyde-3-phosphate dehydrogenase and ubiquitin were used as housekeeping genes. Changes (difference between before and after 48-h infusion) during the infusion period were evaluated by ANOVA with treatment as fixed effect, and area under the curve of variables was calculated on the second day of experiment. The plasma BHBA concentration in HyperB cows was 1.74 ± 0.02 mmol/L (mean ± SE) compared with 0.59 ± 0.02 mmol/L for control cows. The change in feed intake, milk yield, and energy corrected milk did not differ between the 2 experimental groups. Infusion of BHBA reduced the plasma glucose concentration (3.47 ± 0.11 mmol/L) in HyperB compared with control cows (4.11 ± 0.08 mmol/L). Plasma glucagon concentration in HyperB was lower than the control group. All other variables measured in plasma were not affected by treatment. In the liver, changes in mRNA abundance for the selected genes were similar between 2 groups. Results demonstrate that intravenous infusion of BHBA decreased plasma glucose concentration in dairy cows, but this decrease could not be explained by alterations in insulin concentrations or key enzymes related to gluconeogenesis. Declined glucose concentration is likely functionally related to decreased plasma glucagon concentration.

Local and systemic response to intramammary lipopolysaccharide challenge during long-term manipulated plasma glucose and insulin concentrations in dairy cows.

The metabolic load during periods of high milk production in dairy cows causes a variety of changes of metabolite blood concentrations including dramatically decreased glucose levels. These changes supposedly impair the immune system. The goal of this study was, therefore, to evaluate adaptations of the cow's immune system in response to an intramammary lipopolysaccharide (LPS) stimulation during a 3-d modification of plasma glucose and insulin induced by different clamp infusions. Seventeen midlactating dairy cows received a hypoglycemic hyperinsulinemic clamp induced by insulin infusion (HypoG; n=5), a euglycemic hyperinsulinemic clamp induced by insulin and glucose infusion (EuG; n=6), or infusion of saline solution (NaCl; n=6) for 56 h. At 48 h of infusion, 2 udder quarters were challenged with 200 µg of Escherichia coli LPS. At 48 h of infusion (immediately before LPS challenge), tumor necrosis factor α, lactoferrin, and serum amyloid A (SAA) mRNA abundance was increased in HypoG and Il-1ß mRNA abundance was decreased in EuG. After LPS challenge, plasma glucose concentration did not decrease, although plasma insulin increased simultaneously in all groups either due to enhanced endogenous release (NaCl) or due to increased insulin infusion rate (HypoG; EuG). Plasma cortisol, rectal temperatures, and milk somatic cell count of challenged quarters increased, whereas plasma nonesterified fatty acid concentrations were similarly decreased across treatments. In mammary biopsies, increased mRNA expression of tumor necrosis factor α, IL-1ß, IL-8, and IL-10, and SAA were observed in LPS-treated quarters of all groups, with a more pronounced increase in IL-1ß, IL-10, and SAA expression in EuG. Nuclear factor-κB mRNA expression was upregulated in NaCl and EuG but not in HypoG in response to LPS. Lactoferrin, toll-like receptor 4, and cyclooxygenase-2 mRNA expression was increased in LPS-treated quarters of EuG only, and 5-lipoxygenase mRNA expression was decreased in LPS-treated quarters only in treatments HypoG and NaCl. In conclusion, intramammary LPS induces local and systemic inflammatory responses, as well as systemic insulin resistance. The observed treatment differences of the mammary mRNA expression of several immune parameters both before and after LPS challenge indicate a direct influence of changed glucose and insulin concentrations during the course of lactation on the immune defense against mastitis pathogens.

Induced hypoglycemia for 48 hours indicates differential glucose and insulin effects on liver metabolism in dairy cows.

Hypoglycemia is a characteristic condition of early lactation dairy cows and is subsequently dependent on, and may affect, metabolism in the liver. The objective of the present study was to investigate the effects of induced hypoglycemia, maintained for 48 h, on metabolic parameters in plasma and liver of mid-lactation dairy cows. The experiment involved 3 treatments, including a hyperinsulinemic hypoglycemic clamp (HypoG, n=6) to obtain a glucose concentration of 2.5 mmol/L, a hyperinsulinemic euglycemic clamp (EuG, n=6) in which the effect of insulin was studied, and a control treatment with a 0.9% saline solution (NaCl, n=6). Blood samples for measurements of insulin, metabolites, and enzymes were taken at least once per hour. Milk yield was recorded and milk samples were collected before and after treatment. Liver biopsies were obtained before and after treatment to measure mRNA abundance by real-time, quantitative reverse transcription-PCR of 12 candidate genes involved in the main metabolic pathways. Milk yield decreased in HypoG and NaCl cows, whereas it remained unaffected in EuG cows. Energy-corrected milk yield (kg/d) was only decreased in HypoG cows. In plasma, concentration of ß-hydroxybutyrate decreased in response to treatment in EuG cows and was lower (0.41±0.04 mmol/L) on d 2 of the treatment compared with that in HypoG and NaCl cows (on average 0.61±0.03 mmol/L, respectively). Nonesterified fatty acids remained unaffected in all treatments. In the liver, differences between treatments for their effects were only observed in case of mitochondrial phosphoenolpyruvate carboxykinase (PEPCKm) and glucose-6-phosphatase (G6PC). In HypoG, mRNA abundance of PEPCKm was upregulated, whereas in EuG and NaCl cows, it was downregulated. The EuG treatment downregulated mRNA expression of G6PC, a marked effect compared with the unchanged transcript expression in NaCl. The mRNA abundance of the insulin receptor remained unaffected in all treatments, and no significant treatment differences were observed for genes related to lipid metabolism. In conclusion, low glucose concentrations in dairy cows affect liver metabolism at a molecular level through upregulation of PEPCKm mRNA abundance. Metabolic regulatory events in the liver are directed, apart from hormones, by the level of metabolites, either in excess (e.g., free fatty acids) or in shortage (e.g., glucose).

A first national prevalence estimate of diagnosed and undiagnosed diabetes in France in 18- to 74-year-old individuals: the French Nutrition and Health Survey 2006/2007.

AIMS: To estimate the nationwide prevalence of diagnosed and undiagnosed diabetes and pre-diabetes in adults residing in France. METHODS: A probability sample of a non-institutionalized civilian population residing throughout the whole of continental France was recruited from February 2006 to March 2007 for the French Nutrition and Health Survey. All individuals aged between 18 and 74 years who agreed to participate in the survey were included; thus there were 3115 participants, 2102 of whom were undergoing biochemical assessments. The prevalence of diagnosed diabetes was estimated using self-reported diabetes history and the prevalence of undiagnosed diabetes was estimated using fasting plasma glucose ≥ 7.0 mmol/l or HbA(1c) ≥ 6.5% (≥ 48 mmol/mol). RESULTS: The prevalence of diagnosed diabetes was 4.6%, 95% CI 3.6-5.7. The prevalence of undiagnosed diabetes according to standard fasting plasma glucose criteria was 1% (95% CI 0.6-1.7) and contributed to less than 20% of all cases of diabetes. This proportion decreased with age from 30% in 30- to 54-year-olds to 12% in 55- to 74-year-olds. Based on HbA(1c) criteria, the prevalence of undiagnosed diabetes was 0.8% (95% CI 0.4-1.6). CONCLUSIONS: The prevalence of diagnosed diabetes in adults in France is comparable with recent estimates from Northern Europe. The percentage of total diabetes that is undiagnosed is low in France, which may be explained by a widely practised strategy of opportunist screening. During the past years, improvements in diabetes care and increased awareness may have contributed towards decreasing the prevalence of undiagnosed diabetes more widely in Europe, and studies should further monitor such improvements.

Effect of motor imagery in the rehabilitation of burn patients.

Although there is ample evidence that motor imagery (MI) improves motor performance after CNS injury, it is still unknown whether MI may enhance motor recovery after peripheral injury and most especially in the rehabilitation of burn patients. This study aimed to investigate the effects of a 2-week MI training program combined with conventional rehabilitation on the recovery of motor functions in handed burn patients. Fourteen patients admitted to the Medical Burn Center were requested to take part in the study and were randomly assigned to the imagery or the control group. Behavioral data related to the ability to perform each successive step of three manual motor sequences were collected at five intervals during the medical procedure. The results provided evidence that MI may facilitate motor recovery, and the belief in the effectiveness of MI was strong in all patients. MI may substantially contribute to improve the efficacy of conventional rehabilitation programs. Hence, this technique should be considered as a reliable alternative method to help burn patients to recover motor functions.

The incidence and persistence of the NCEP (National Cholesterol Education Program) metabolic syndrome. The French D.E.S.I.R. study.

CONTEXT: In 2001 the "National Cholesterol and Education Program Expert Panel" gave a clinical definition of the metabolic syndrome. The frequency of this syndrome at baseline and its incidence and persistence at three years is studied in a French population. SUBJECTS: 2109 men and 2184 women from the D.E.S.I.R. longitudinal cohort study (Data from an Epidemiological Study on the Insulin Resistance syndrome) in central-western France, aged 30 to 64 years, were examined at inclusion and three years later. METHODS: Evaluation of the frequencies, incidences and persistence of the metabolic syndrome and its abnormalities. This syndrome is defined by the presence of three or more of five abnormalities: waist circumference > 102/88 cm (men/women); triglycerides > o r=1.69 mmol/l, HDL-cholesterol<1.04/1.29 mmol/l (men/women); systolic/diastolic blood pressure > or =130 and/or 85 mmHg; fasting plasma glucose > or =6.1 mmol/l. RESULTS: At baseline, 10% of men and 7% of women had the metabolic syndrome. If the syndrome was defined to include a treatment in the abnormalities (for diabetes, hypertension, dyslipidemia), the syndrome frequencies increased to 16% and 11%. However only 12% and 8% respectively, had this syndrome both at inclusion and at three years. High blood pressure was the most frequent abnormality: 70% and 47% in men and women respectively, at inclusion. The most stable abnormality was high waist circumference (80% persisted), hyperglycaemia the least stable (60% persisted). Hyperinsulinaemia did not cluster closely with this syndrome. CONCLUSIONS: The age-specific frequency of the syndrome is more than 2.5 times higher in the US than in this French cohort and this ratio increased with age. The higher frequencies of abdominal obesity and low HDL-cholesterol in women than in men suggest that these gender-specific thresholds may need to be refined.

[Geographic distribution of surnames and genetic structure: the county of Ardeche at the beginning of the twentieth century]. / Répartition géographique des patronymes et structure génétique: le département de l'Ardèche au début du XXe siècle.

The analysis of the geographical distribution of surnames (whose transmission in the European societies is similar to that of the Y chromosome) allows to study in an exhaustive way the spatial and temporal human population structure and the influence of environmental variations on this structure. The genetic structure of the Ardèche county was analysed through a study of the surname characteristics (diversity, frequency, geographical dispersion, etc.) of individuals born between 1891 and 1915. The estimation of the intra-community average consanguinity and the inter-district genetic relationships reveals a clear differentiation between populations of the mountainous part (geographically isolated, highly inbred) and those of the Rhône valley (less isolated, weakly inbred). As predicted by the isolation by distance model, inter-population coefficients of kinship decreases as distance increases, confirming the presence of a spatial structure, characterized by neighborhood exchange and resulting from former migratory flow.

The distribution and geographical origin of some French surnames.

The geographical distribution of the principal form of a French surname and its close variants (in spelling or pronunciation) has been analysed based on the French births registers, respectively from 1891 to 1915 and from 1916 to 1940, and on telephone directories for 1975. The spatial analysis of the individuals with the principal form of the surname suggests the existence of a positive spatial autocorrelation and three major areas of concentration in central France, the Loire country and Northern France. Within these three main areas of concentration, in 1975 most of the telephone subscribers with the principal surname are listed in rural communes with fewer than 3000 inhabitants, suggesting that the geographical pattern is not recent. Moreover, between the end of the 19th century and 1975 this pattern remains fairly constant. The geographical distribution of the holders of a 'variant' form of the surname shows the existence of a positive correlation between the absolute frequency of the principal surname and that of the variants, but only one area of concentration appears in Loire country. By analogy with the theory of centres of origin in genetics and linguistics, it is suggested that this unique area of concentration could be the region in which the surname originated. If that hypothesis proves to be correct, two main consequences follow: large migration movements occurred before the general rural exodus of the last century, and there has been no major, recent admixture of populations.

Trends in inbreeding, isonymy, and repeated pairs of surnames in the Valserine Valley, French Jura, 1763-1972.

The estimates of inbreeding derived from pedigrees and frequency of isonymous marriages (i.e., between persons of the same surname) are compared using genealogical and isonymic information from 4,899 marriages recorded between 1763 and 1972 in 4 rural villages of the French Jura region (a mountainous area near the Swiss border). Before the second half of the 20th century, the two kinds of estimates show a different temporal evolution. The mean inbreeding coefficient based on pedigrees increases between 1763 and 1852 and reaches a maximum between 1853 and 1882 (alpha = 0.0028), with a very low percentage (< 1%) the result of remote kinship. The mean inbreeding coefficient based on isonymy is always higher, with a maximum observed between 1793 and 1822 (F = 0.0200), and it remains roughly the same between 1763 and 1882 (F = 0.0150), with a high percentage resulting from a random component (Fr), a consequence of the small population size and genetic drift. After 1883, the 2 mean coefficients decrease. This discordance is largely explained by the poor quality, for the first periods, of the genealogical data base, which ignores the more remote links of kinship, justifying the use of the model of Crow and Mange (1965) to explore consanguinity during the more ancient periods. The temporal evolution of the repeated pairs of surnames index (RP) confirms the recent evolution of the marital structure of the valley. Moreover, it appears that isonymous marriages and repeated and unique pairs of surnames constitute 3 distinct matrimonial groups characterized by both a different mean coefficient of inbreeding (alpha) and a different rate of endogamy.

Effects of dietary calcium soaps of unsaturated fatty acids on digestion, milk composition and physical properties of butter.

Dairy cows fitted with ruminal, duodenal and ileal cannulas were utilized to investigate the effects of feeding with Ca soaps (CaS) of palm fatty acids (FA) and rapeseed FA. Diets compared were control diet based on maize silage and concentrate, and two diets with 40 g CaS of palm oil FA or rapeseed oil FA/kg diet, replacing part of the concentrates of the control diet. Total digestibilities of dry matter, fibre and fat, and ruminal fermentation were not significantly altered by giving CaS; the extent of ruminal biohydrogenation of total unsaturated C18 FA was significantly reduced by both CaS diets. Apparent intestinal digestibility of FA was not different among diets, although the amount of FA absorbed with the CaS diets was twice that with the control diet. No difference among diets was observed for milk production, or fat and protein contents. Giving CaS diets decreased the proportions of 4:0 to 14:0 FA in milk fat, and increased cis-18:1n-9, compared with control diet. The rapeseed diet lowered the content of 16:0, and increased the contents of 18:0 and trans-18:1n-7. CaS diets did not result in a marked increase of polyunsaturated FA content in milk fat. Butter from cows fed on the CaS diets contained more liquid fat at 6 and 14 degrees C than butter from the cows fed on the control diet. Incorporating CaS, particularly those from rapeseed, in dairy cows' diets increased C18 FA in milk and improved butter spreadability.

In vivo study of circadian variations of the cecal fermentation pattern in postweaned and adult rabbits.

Two groups of cecal cannulated rabbits (postweaned and adult, 6 and 16 wk of age, respectively) were used to compare the circadian variations of the fermentation pattern. Rabbits were kept in metabolism cages under a 12:12 light-dark schedule (0700 to 1900). For each rabbit, a total of 12 samples of cecal material were collected (every 12 h) for six consecutive days to cover a 24-h cycle; feed ingestion and hard feces elimination were recorded. For postweaned and adult rabbits, the period of cecotrophy practice was mainly 0400 to 1200, and also 2200 to 2400 for the former and 0800 to 1400 for the later. Compared with those of adult rabbits, the cecal contents of the postweaned rabbits were characterized by a lower DM level (17.6 vs 20.3%; P < .001), a lower VFA level (65.4 vs 86.1 mM; P < .001), and a higher ammonia N level (7.6 vs 6.1%; P = .02) related to the presence of a double period of cecotrophy (only one in the adult rabbits), and corresponding to the postweaning adaptation of the cecal microflora to a dry feed. A lower butyrate molar proportion was found in postweaned than in adult rabbits (10.5 vs 13.6%; P = .004), whereas molar proportion of acetate and propionate remained similar regardless of the age of the rabbit. In the postweaned rabbits, changes in fermentation pattern were related to circadian rhythm of the cecotrophy practice. During this period, the levels of total VFA, acetate, and butyrate progressively decreased; the minimum was reached at 1200 (e.g., 53.8 44.6, and 4.4 mM, respectively); the corresponding propionate:butyrate ratio was 1.0.

Effects of extrusion of whole horse beans on protein digestion and amino acid absorption in dairy cows.

Four lactating cows fitted with ruminal, duodenal, and ileal cannulas were used to determine the effects of extrusion of whole horse beans on ruminal CP degradation and absorption of AA from the small intestine. Diets contained 15% CP, of which 46% was provided by the raw or extruded whole horse beans. Spot samples of duodenal and ileal digesta were collected during a 72-h period. The markers Cr-EDTA, YbCl3, and purines were used for liquid, particulate, and bacteria, respectively. Extruded whole horse beans increased AA flow to the duodenum and disappearance in the small intestine. Diets containing extruded whole horse beans increased availability of total essential AA in the small intestine compared with diets containing raw whole horse beans.

Effects of a supply of raw or extruded white lupin seeds on protein digestion and amino acid absorption in dairy cows.

Four cannulated, lactating cows were used to determine the effects of extruding white lupin seeds (WLS) on intraruminal CP degradation and absorption of AA from the small intestine. Raw lupin seeds (RWLS) and extruded lupin seeds (EWLS) were fed in diets containing 15.5% CP and composed of 22.4% WLS, 55.9% corn silage, 10.1% maize grain, and 10.6% Italian ryegrass on a DM basis; WLS provided approximately 50% of the total dietary CP. Spot samples of digesta were collected from the proximal duodenum and terminal ileum during 72 h. Chromium EDTA, YbCl3, and purines were used as liquid, particulate, and bacterial markers, respectively. Because of the extensive ruminal degradation of dietary N with the RWLS diet compared with the EWLS diet (64.2 vs 38.8%), less total AA flowed to the duodenum (1,748 vs 2,347 g/d), and because of the decrease of availability (67.2 vs 79.0% of entering), absorption from the small intestine was lowest with this diet (1,175 vs 1,855 g/d). The apparent digestion of individual AA in the small intestine (percentage entering) ranged from 46.5 to 88.4 when cows consumed RWLS and from 58.9 to 94.4 when they were fed the EWLS diet. Among the diets, apparent absorption of histidine, lysine, glycine, and serine were higher than those of other AA; also, valine, alanine, and proline showed intestinal absorptions that were somewhat lower than those of the remainder of the AA.

Effect of protein-protected fat on ruminal and total nutrient digestibility of sheep diets.

Experiments were conducted to determine the effects of supplementing chopped ryegrass hay with 0, 5, 10, or 20% fat coated with ruminal bypass protein (Prolip on ruminal digestion by cows and nutrient digestibility by sheep. Ruminal disappearances of DM, ADF, and NDF were measured by the in sacco technique using a cannulated cow. Degradation of DM, ADF, and NDF was not affected by protected fat supplementation at the 5, 10, or 20% level during the first 16 h in the rumen. In addition, supplementation with Prolip did not influence in vitro fermentation characteristics such as pH and VFA patterns. A digestibility experiment with six mature sheep in a switch-back design showed no decrease in feed intake or other undesired effects between unsupplemented (basal) and Prolip-supplemented diets. Whatever the diet fed to sheep, fiber digestibility was similar; however, DM and nitrogen digestibilities were significantly higher relative to the basal diet when ryegrass hay was substituted at 20% (64.2 vs 59.0% and 74.1 vs 71.1%, respectively). Ether extract digestion was enhanced by increasing level of Prolip; the corresponding values were 48.0, 64.9, 74.6, and 84.6% at 0, 5, 10, or 20% Prolip. Likewise, Prolip supplementation at the 10 or 20% level augmented digestibility of energy (62.7 or 65.9 vs 59.2%). Nitrogen and energy retentions were improved due to the decreases in fecal and(or) urinary excretion(s).