Effects of flaxseed supplementation on milk production, milk fatty acid composition and nutrient utilization by lactating dairy cows

Twelve multiparous Holstein cows at 72 +/- 20 days in milk were used in a switch-back design with 14-d periods to determine the effect of replacing barley grain into a dairy total mixed ration with micronized or raw flaxseed on nutrient digestibility, milk yield, milk composition. Total mixed diets were (DM basis) 50% barley silage, 50% concentrate mix mainly rolled barley grain and canola meal. Diets were supplemented with 1 kg raw (RF) or micronized (MF) flaxseed to substitute 1 kg of rolled barley grain (C). Neutral detergent fibre, ADF and CP digestibility of the diets were not significantly affected by supplementation; however, calcium digestibility was reduced by 62% and 46% when raw and micronized flax were fed, respectively. Milk yield (38.3, 39.6, and 38.4 kg/d for diets C, RF and MF, respectively) was similar for all diets. Milk fat (3.50, 3.48, and 3.52%) and protein (3.31, 3.34, and 3.31%) for diets C, RF and MF, respectively, were not affected by treatment diets. Concentrations of c9, t11 conjugated linoleic acid (CLA; 0.51, 0.72 and 0.76 g/100 g fatty acids) in milk fat increased (P<0.05) similarly among the two flaxseed supplemented diets. The RF and MF diets significantly increased the C18:1, C18:1 trans-11, C18:2 cis-9, cis-12 and C18:3 in milk fat however, C12:0, C14:0 and C16:0 were significantly reduced compared with control. Replacing barley grain with flaxseed in the diet of lactating cows increased the beneficial fatty acids in milk without depressing nutrient digestibility. Micronization of flaxseed did not reveal any advantage over raw flaxseed.

KATP channels mediate adenosine-induced hyperemia in retina

PURPOSE

The authors and others have shown previously that the purine nucleoside adenosine is a potent vasodilator in the retinal microcirculation, mediating increases in retinal blood flow (RBF) in response to several autoregulatory stimuli. The current experiments were undertaken to elucidate the involvement of adenosine triphosphate (ATP)-sensitive potassium (KATP) channels and the adenylate cyclase--cyclic adenosine monophosphate (cAMP) second-messenger system in the transduction of adenosine's hyperemic response.

METHODS

Retinal fluorescein angiograms were videorecorded in isoflurane-anesthetized newborn pigs, and changes in arteriovenous transit times and retinal arteriolar and venular diameters were used to estimate stimulus-induced changes in RBF.

RESULTS

Intravitreal perivascular microsuffusion of 5 nmol and 50 nmol adenosine caused dose-dependent increases in RBF of 79% +/- 4% (P < 0.05; n = 5) and 323% +/- 61% (P < 0.05; n = 5), respectively. The KATP channel antagonist glibenclamide (0.5 nmol and 5 nmol) caused a significant, dose-dependent attenuation of the hyperemic response to 5 nmol adenosine. The specificity of glibenclamide for blocking KATP channels was demonstrated by its ability to block by 94% +/- 6% (P < 0.05; n = 5) the increase in RBF (94% +/- 7%; P < 0.05) elicited by the intravitreal microsuffusion of the KATP channel agonist cromakalim (5 nmol), whereas it had no effect on the 103% +/- 12% increase in RBF (P < 0.05; n = 5) induced by the nitric oxide donor sodium nitroprusside (15 nmol). Adenosine-induced hyperemia was not potentiated by forskolin (1.7 nmol; n = 4), an adenylate cyclase activator, and was not attenuated by dideoxyadenosine (5 nmol; n = 4), an adenylate cyclase inhibitor. In addition, no significant increases in RBF could be elicited by 2.5 to 25 nmol 8-bromo-cAMP (n = 4), a membrane-permeable cAMP analog.

CONCLUSIONS

These results in the piglet indicate that adenosine increases blood flow in the retina by activating KATP channels, not by increasing in cyclic AMP secondary to adenylate cyclase activation. They also underscore the potential importance of KATP channels in the transduction of retinal vasodilatative responses to other agonists.

Transition strategies: moving systems from old to new

Healthcare institutions today are finding their information systems inadequate. Providers want systems that integrate clinical and financial information as well as support strategic decision making. To support these needs and wants, more organizations are investing in new and more technologically advanced information systems. By looking at three separate scenarios that present circumstances which are common to healthcare organizations, this article presents guidelines that enable an institution to assess its current information systems and discusses options available to help organizations make the transition from old systems to new.