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1.
Transl Anim Sci ; 7(1): txac166, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36816826

RESUMEN

The U.S. pork production system is sensitive to supply chain disruptions, including those that can create challenges of feed delivery and feed management during the event of a foreign animal disease outbreak. Therefore, the objective was to evaluate feeding strategies during a prolonged feed availability shortage in group-housed finishing pigs and assess the impacts on pig performance. A total of 1,407 mixed-sex pigs (92 ± 11 kg BW) were randomly allocated to one of five treatments across 60 pens (N = 12 pens per treatment, 22 pigs per pen) and were blocked by initial body weight (BW) within the replicate, over a 21-d test period. Treatments were fed for 14 d (P1), and thereafter all pens returned to ad libitum access to a standard commercial diet for 7 d (P2). Treatments included: 1) Pens fed ad libitum (CON); 2) Pens fed at 1.45X ME maintenance requirement daily of CON diet (1.45X); 3) Pens fed 2X ME maintenance requirement daily of CON diet (2X); 4) Tightened feeders to the lowest setting, fed ad libitum of CON diet (CF); and 5) whole corn kernels, fed ad libitum (WC). P1 and P2 BW and feed disappearance were recorded to calculate ADG, ADFI, and G:F. Data were analyzed with pen as the experimental unit and least-squares means values reported by treatment. Compared to CON, pens fed 1.45X, 2X, CF, and WC treatments had significantly reduced P1 ADG (1.09 vs. 0.02, 0.34, 0.72, 0.41 kg/d, respectively), ADFI (3.21 vs. 1.42, 1.90, 2.49, 2.40 kg/d, respectively) and G:F (P < 0.05). During P2, ADG and G:F were increased (P < 0.05) compared to CON across all treatments. However, ADFI increased only in the 2X, CF, and WC diet from the CON (P < 0.05). Overall (days 0 to 21), all strategies attenuated BW, ADG, and ADFI (P < 0.01) compared to CON. However, G:F was only reduced (P < 0.01) in 1.45X and WC, but not 2X and CF (P > 0.05) compared to CON. In conclusion, all strategies explored could extend feed budgets. Even though these strategies were successful, increased BW variability was reported with more restrictive strategies. Further, adverse pig behaviors and welfare implications needs to be considered in adopting any restrictive feeding strategy.

2.
J Appl Physiol (1985) ; 133(6): 1407-1414, 2022 12 01.
Artículo en Inglés | MEDLINE | ID: mdl-36326473

RESUMEN

Patients with type 2 diabetes mellitus (T2DM) have reduced exercise capacity, indexed by lower maximal oxygen consumption (V̇o2max) and achievement of the gas exchange threshold (GET) at a lower % V̇o2max. The ubiquitous signaling molecule nitric oxide (NO) plays a multifaceted role during exercise and, as patients with T2DM have poor endogenous NO production, we investigated if inorganic nitrate/nitrite supplementation (an exogenous source of NO) improves exercise capacity in patients with T2DM. Thirty-six patients with T2DM (10F, 59 ± 9 yr, 32.0 ± 5.1 kg/m2, HbA1c = 7.4 ± 1.4%) consumed beetroot juice containing either inorganic nitrate/nitrite (4.03 mmol/0.29 mmol) or a placebo (0.8 mmol/0.00 mmol) for 8 wk. A maximal exercise test was completed before and after both interventions. V̇o2max was determined by averaging 15-s data, whereas the GET was identified using the V-slope method and breath-by-breath data. Inorganic nitrate/nitrite increased both absolute (1.96 ± 0.67 to 2.07 ± 0.75 L/min) and relative (20.7 ± 7.0 to 21.9 ± 7.4 mL/kg/min, P < 0.05 for both) V̇o2max, whereas no changes were observed following placebo (1.94 ± 0.40 to 1.90 ± 0.39 L/min, P = 0.33; 20.0 ± 4.2 to 19.7 ± 4.6 mL/kg/min, P = 0.39). Maximal workload was also increased following inorganic nitrate/nitrite supplementation (134 ± 47 to 140 ± 51 W, P < 0.05) but not placebo (138 ± 32 to 138 ± 32 W, P = 0.98). V̇o2 at the GET (1.11 ± 0.27 to 1.27 ± 0.38L/min) and the %V̇o2max in which GET occurred (56 ± 8 to 61 ± 7%, P < 0.05 for both) increased following inorganic nitrate/nitrite supplementation but not placebo (1.10 ± 0.23 to 1.08 ± 0.21 L/min, P = 0.60; 57 ± 9 to 57 ± 8%, P = 0.90) although the workload at GET did not achieve statistical significance (group-by-time P = 0.06). Combined inorganic nitrate/nitrite consumption improves exercise capacity, maximal workload, and promotes a rightward shift in the GET in patients with T2DM. This manuscript reports data from a registered Clinical Trial at ClinicalTrials.gov ID: NCT02804932.NEW & NOTEWORTHY We report that increasing nitric oxide bioavailability via 8 wk of inorganic nitrate/nitrite supplementation improves maximal aerobic exercise capacity in patients with type 2 diabetes mellitus. Similarly, we observed a rightward shift in the gas exchange threshold. Taken together, these data indicate inorganic nitrate/nitrite may serve as a means to improve fitness in patients with type 2 diabetes mellitus.


Asunto(s)
Beta vulgaris , Diabetes Mellitus Tipo 2 , Humanos , Tolerancia al Ejercicio , Nitratos , Diabetes Mellitus Tipo 2/tratamiento farmacológico , Óxido Nítrico , Suplementos Dietéticos , Estudios Cruzados , Método Doble Ciego , Consumo de Oxígeno
3.
Am J Physiol Regul Integr Comp Physiol ; 323(5): R787-R796, 2022 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-36154488

RESUMEN

Intermittent (IH), as opposed to continuous hypoxia (CH), is thought to have beneficial effects on cardiovascular function and health. In the present study, we examined the acute effects of IH and CH (∼80% pulse oxygen saturation via 10% oxygen tank) on peripheral vascular function. Brachial artery flow-mediated dilation (FMD) was used to assess vascular function in 12 young adults (23 ± 5 yr; 8 M/4 F) before and after 50 min of IH (5 cycles; 4-min normoxia/6-min hypoxia per cycle), CH (20-min normoxia followed by 30-min hypoxia), or time control (50-min normoxia) interventions. Brachial artery diameter and velocity were measured using Doppler ultrasound to assess blood flow and shear rate. The total change in shear rate was greater during IH (634 ± 1,073·s-1, P < 0.05) and CH (321 ± 833·s-1, P = 0.05) than during time control (-412 ± 789·s-1). %FMD was reduced following time control (7.4 ± 1.2 to 5.9 ± 1.1%, P < 0.05) but was maintained following both hypoxia trials (IH: 7.2 ± 1.5 to 7.5 ± 1.5%, P = 0.52; CH: 6.9 ± 1.6 to 6.8 ± 1.4%, P = 0.73). Normalized %FMD for shear rate area under the curve (%FMDSRAUC) was reduced following the time control trial (4.2 ± 1.4 to 3.7 ± 0.9%, P < 0.05) with no change observed with CH (4.0 ± 1.5 to 3.9 ± 1.4%, P = 0.71). However, %FMDSRAUC increased with IH (3.8 ± 1.1 to 4.5 ± 1.5%, P < 0.05). Our data suggest that acute exposure to hypoxia (both intermittently and continuously) offsets the decline in vascular function after brief inactivity. The potential beneficial effect of hypoxia on peripheral vascular function observed in the current study may be associated with enhanced brachial artery shear in response to the hypoxic challenge.


Asunto(s)
Arteria Braquial , Hipoxia , Adulto Joven , Humanos , Arteria Braquial/diagnóstico por imagen , Dilatación , Oxígeno , Hemodinámica , Vasodilatación/fisiología , Velocidad del Flujo Sanguíneo , Flujo Sanguíneo Regional/fisiología , Endotelio Vascular
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