Effects of hydrolyzed fish protein and autolyzed yeast as substitutes of fishmeal in the gilthead sea bream (Sparus aurata) diet, on fish intestinal microbiome

Background

This study evaluated the effects of partial substitution of dietary fishmeal (FM) with either fish protein hydrolysate (FPH) or autolysed dried yeast (HiCell®, Biorigin, Brazil) on intestinal microbiota of gilthead sea bream (Sparus aurata). A total number of 720 fish of 122.18 ± 6.22 g were fed for 92 days with three different diets in triplicate (3 tanks/diet). A diet based on FM/vegetable meal was used as control. The other two diets were formulated by replacing FM with 5% of either FPH or HiCell®. To analyze the gut microbiota associated to autochthonous and allochthonous microbial communities, the Illumina MiSeq platform for sequencing of 16S rRNA gene and QIIME pipeline were used.

Results

A total number of 102 OTUs (operational taxonomic units) at 97% identity were identified in fish gut samples collected at the end of feeding trial. Fourteen OTUs constituted the core gut microbiota, i.e. those OTUs found in at least nine out of fifteen samples per group and shared regardless of the diet. Eight OTUs were assigned to Firmicutes represented by Lactobacillus, Staphylococcus, and Bacillus genera, and six to Proteobacteria phylum. Dietary dried yeast autolysate modulated the intestinal microbiota by promoting the growth of some beneficial bacteria. At order level, fish fed yeast showed an enrichment in Bacillales and Clostridiales as compared to the control group, whereas fish fed FPH showed a significantly lower amount of bacteria belonging to Alteromonadales and Enterobacteriales than the other two feeding groups. Although we did not observe any effect of 5% FM replacement with alternative nitrogen sources at phylum level, at lower taxonomical levels, the composition of gut microbiota, in terms of relative abundance of specific taxa, was significantly influenced by the dietary treatment.

Conclusions

The metabarcoding analysis revealed a clearly intestinal microbiota modulation in response to dietary autolyzed yeast. The abundance of some beneficial bacteria, i.e. indigestible carbohydrate degrading- and SCFA producing bacteria, was positively affected. Brewer’s yeast autolysate could be a valid alternative protein source to FM as well as a valid functional ingredient for aquafeed production.

Effect of Home Blood Pressure Monitoring on Patient's Awareness and Goal Attainment Under Antihypertensive Therapy: The Factors Influencing Results in Anti-HypertenSive Treatment (FIRST) Study

BACKGROUND/AIMS

Despite availability of a broad spectrum of blood pressure (BP)-lowering drugs many hypertensive patients do not attain BP goals. We aimed to evaluate the influence of home blood pressure monitoring (HBPM) on patient's awareness and attainment of BP goals under antihypertensive treatment with irbesartan alone or in combination with hydro-chlorothiazide.

METHODS

In total, 1,268 patients with arterial hypertension were enrolled in the Factors Influencing Results in anti-hypertenSive Treatment (FIRST) study by 348 general practitioners and internal medicine specialists across Switzerland. Patients selected for HBPM received detailed information and training on BP self-management. The study endpoints included patient's awareness and attainment of BP goals, and the efficacy and tolerability of antihypertensive treatment at 3 months.

RESULTS

Overall, the mean age was 61±13 years and 616 (49%) were women. The mean systolic/diastolic BP was 161±17/96±11 mmHg, and 239 (19%) patients had diabetes mellitus. 758 (60%) patients were instructed to use HBPM. Both the proportion of patients aware of their BP goals (81% vs. 70%; p< 0.001) and the percentage of patients reaching their BP goal (64% vs. 57%; p=0.028) were higher in those with vs. without HBPM. The mean reduction in systolic/diastolic BP was 23.8/13.2 mmHg. Only 35 (3.0%) patients discontinued antihypertensive therapy.

CONCLUSION

In a large Swiss cohort of patients with arterial hypertension, information and training on BP self-measurement and direct involvement of patients by using HBPM led to improvement in BP control. Treatment with irbesartan alone or in combination with hydrochlorothiazide was well tolerated and markedly reduced BP.

Loss of Sodium/Hydrogen Exchanger NHA2 Exacerbates Obesity- and Aging-Induced Glucose Intolerance in Mice

We previously demonstrated that the sodium/hydrogen exchanger NHA2, also known as NHEDC2 or SLC9B2, is critical for insulin secretion by β–cells. To gain more insights into the role of NHA2 on systemic glucose homeostasis, we studied the impact of loss of NHA2 during the physiological aging process and in the setting of diet-induced obesity. While glucose tolerance was normal at 2 months of age, NHA2 KO mice displayed a significant glucose intolerance at 5 and 12 months of age, respectively. An obesogenic high fat diet further exacerbated the glucose intolerance of NHA2 KO mice. Insulin levels remained similar in NHA2 KO and WT mice during aging and high fat diet, but fasting insulin/glucose ratios were significantly lower in NHA2 KO mice. Peripheral insulin sensitivity, measured by insulin tolerance tests and hyperinsulinemic euglycemic clamps, was unaffected by loss of NHA2 during aging and high fat diet. High fat diet diminished insulin secretion capacity in both WT and NHA2 KO islets and reduced expression of NHA2 in WT islets. In contrast, aging was characterized by a gradual increase of NHA2 expression in islets, paralleled by an increasing difference in insulin secretion between WT and NHA2 KO islets. In summary, our results demonstrate that loss of the sodium/hydrogen exchanger NHA2 exacerbates obesity- and aging-induced glucose intolerance in mice. Furthermore, our data reveal a close link between NHA2 expression and insulin secretion capacity in islets.

Abstract 092: Low Birth Weight per se Is Not a Determinant of Vascular Dysfunction and Presumably Future Cardiovascular Risk in Humans

Background: Epidemiological studies suggest that low birth weight (BW) is associated with systemic vascular dysfunction and premature cardiovascular morbidity and mortality later in life. However, this association could be due to confounding factors associated with low BW, such as genetic factors, pathological events during intrauterine life, and maternal or early-life environmental insults. Studies of monozygotic twins born with significantly different BW provide a unique opportunity to control for these potential confounding factors, thereby allowing to directly study the effect of low BW per se on systemic vascular function later in life.

Methods: We, therefore, measured flow-mediated dilation (FMD) of the brachial artery, carotid-femoral pulse wave velocity (PWV) and carotid intima-media thickness (IMT) in 13 monozygotic, monochorionic healthy twins pairs (mean±SD age, 13.5±3.4 years) who were born with significantly different BW (defined as >20% BW difference within pairs, 2310±600 vs. 1800±520 g, P<0.0001) and in 26 healthy age- and sex-matched control subjects born at term with normal BW (3460±360 g). None of the participants had suffered from intrauterine or perinatal complications.

Results: The major new findings were two fold; 1) systemic vascular function was comparable in low and high BW twins (FMD, 9.0±1.8 vs. 8.7±2.0%; PWV, 6.5±1.3 vs. 6.6±0.9 m/s; IMT, 390±30 vs. 390±20μm, all P values >0.2, low vs. high BW) and 2) systemic vascular function in twins was similar to the one observed in control singletons (FMD, 8.8±1.3 vs.8.9±1.8%, P=0.95; PWV: 6.5±1.1 vs. 6.6±1.2 m/s, P=0.80; IMT: 390±25 vs. 385±20μm, P=0.33, singletons vs. twins). Finally, there existed no relationship between BW and vascular function in the whole study population (FMD: r=0.001, P=0.99).

Conclusions: This study provides the first direct evidence in humans that low BW per se is not a determinant of systemic vascular dysfunction (and presumably future cardiovascular risk). Moreover, it indicates that independent of BW, vascular function in twins is normal. We suggest that the association between low BW and increased cardiovascular risk reported in earlier epidemiological studies was related to confounding factors associated with low BW.

Sulfhydryl G proteins and phospholipase A(2)-associated G proteins are involved in adrenergic signal transduction in the rat pineal gland

The rat pineal gland with its circadian noradrenaline-regulated melatonin rhythm is an excellent model for studying adrenergic signal transduction with respect to cAMP and cGMP formation. The stimulatory G(s) proteins play a well-established role in this process. In contrast, the potential roles of the inhibitory G(i) proteins, the functionally unclear other G(o) proteins, and a number of G protein subtypes are not known. The present study examines the effects on beta(1)- and beta(1)-plus-alpha(1)-stimulated cAMP and cGMP formation of a number of G protein modulators in rat pinealocyte suspension cultures. The effects of the nitric oxide donor sodium nitroprusside on cGMP were also examined. The results showed that drugs that activate G proteins of the G(i)/G(o) family, i.e., pertussis toxin, mastoparan, and compound 48/80, had no effect on unstimulated, isoproterenol (beta(1))-stimulated, or combined isoproterenol/phenylephrine (beta(1)-plus()-alpha(1))-stimulated cAMP and cGMP accumulation. However, in this experimental paradigm, the inhibitors of sulfhydryl G proteins (N-ethylmaleimide) and those of phospholipase A2-related G proteins (isotetrandrine) exerted a clear inhibitory effect. Sodium-nitroprusside-stimulated cGMP accumulation was also inhibited. These results confirm a previous report that members of the G(i)/G(o) family, which are present in the rat pineal gland, do not play a major role in adrenergic signal transduction. The new finding that sulfhydryl G proteins and phospholipase A2-associated G proteins exert a clear stimulatory effect on adrenergic signal transduction suggests that they are subtypes of G(s) proteins.

Circadian rhythm and effects of light on cAMP content of the dwarf hamster suprachiasmatic nucleus

The present study was conducted in the dwarf hamster (Phodopus sungorus) to investigate whether a circadian rhythm is present in the content of the second messenger cyclic adenosine 3',5'-monophosphate (cAMP) in the suprachiasmatic nucleus (SCN), the endogenous clock in mammals. In animals held under light/dark conditions (LD), we observed high levels at the end of the light phase and low levels during the night in frozen SCN punches. In animals held in continuous dark, a similar rhythm was seen although a second peak was present in the subjective day. In senile hamsters under LD, the decrease of cAMP levels at the light transition was not seen. These data, obtained for the first time from hamsters, support the view that cAMP is involved in time-keeping mechanisms within the SCN.