Sexual dimorphism in histological characteristics and contractility of the iliofibularis muscle in the lizard Sceloporus torquatus

Our results and observations support the idea that muscle characteristics are coadaptations of organisms and environment, as noted by Bonine et al. (2001). What we need to know now is whether and how the environment affects the relationship between muscle phenotype and fitness. Therefore, studies on habitat, behavioural patterns, morphological characteristics and locomotor performance are needed to better understand the plasticity of the locomotor muscles.The iliofibularis is a hindlimb muscle used in lizard locomotion that is composed of at least three types of fibres: fast-twitch-glycolytic (FG), fast-twitch-oxidativeglycolytic fibre (FOG) and slow-twitch-oxidative (SO). The striated skeletalmuscle is a highly plastic tissue undergoing phenotypic change in response to activity. The lizard Sceloporus torquatus has sexual differences associated with microhabitat use, which can be reflected in the physiology and anatomy of the muscle, and thus, in our study, we analysed the morphological and contractile characteristics of the iliofibularis muscle (IF) of S. torquatus males and females. We found a larger prevalence of FOG compared with FG and SO fibres in the muscle of both sexes. We also found that males show larger areas of the three types of fibres, develop greater strength but also faster fatigue than females, suggesting that strength is a key functional feature that enables males to perform faster movements (but for shorter periods), associated with the demands of territoriality.CONACYT 226935/21266

Individualistic responses of forest herb traits to environmental change

Intraspecific trait variation (ITV; i.e. variability in mean and/or distribution of plant attribute values within species) can occur in response to multiple drivers. Environmental change and land-use legacies could directly alter trait values within species but could also affect them indirectly through changes in vegetation cover. Increasing variability in environmental conditions could lead to more ITV, but responses might differ among species. Disentangling these drivers on ITV is necessary to accurately predict plant community responses to global change. We planted herb communities into forest soils with and without a recent history of agriculture. Soils were collected across temperate European regions, while the 15 selected herb species had different colonizing abilities and affinities to forest habitat. These mesocosms (384) were exposed to two-level full-factorial treatments of warming, nitrogen addition and illumination. We measured plant height and specific leaf area (SLA). For the majority of species, mean plant height increased as vegetation cover increased in response to light addition, warming and agricultural legacy. The coefficient of variation (CV) for height was larger in fast-colonizing species. Mean SLA for vernal species increased with warming, while light addition generally decreased mean SLA for shade-tolerant species. Interactions between treatments were not important predictors. Environmental change treatments influenced ITV, either via increasing vegetation cover or by affecting trait values directly. Species' ITV was individualistic, i.e. species responded to different single resource and condition manipulations that benefited their growth in the short term. These individual responses could be important for altered community organization after a prolonged period

Toward an Improved Conceptual Understanding of North American Tree Species Distributions

Species distributions have often been assumed to represent climatic limitations, yet recent evidence has challenged these assumptions and emphasized the potential importance of biotic interactions, dispersal limitation, and disturbance. Despite significant investigation into these factors, an integrated understanding of where and when they may be important is lacking. Here, we review evidence for the factors underlying the historical and contemporary distributions of North American tree species and argue that a cohesive conceptual framework must be informed by an understanding of species ecological and evolutionary history. We further demonstrate that available evidence offers little indication of a significant, independent influence of biotic interactions or dispersal limitation on species distributions. Disturbance may provide important constraints on distributions in limited contexts. Overall, historic and contemporary evidence suggests that species distributions are strongly influenced by climate, yet examples of disequilibrium with climate abound. We propose that differences among life stages and the impacts of human land use may contribute to explain these inconsistencies and are deserving of greater research attention

Addressing sustainable ruminal methane and carbon dioxide emissions of soybean hulls by organic acid salts

Agriculture wastes are carbohydrate-rich feeds with a large potential source of dietary energy for ruminants, but in developing countries, they always constitute environmental problems when burnt in the field, and can be used as a cleaner product of animal feed and environment (Kholif et al., 2014). However, intensive ruminant production requires high concentrate diets to assure high productivity and fast growth. Cereals, such as barley, wheat and corn, are commonly used for intensive ruminant production.emissions as well as ruminal fermentation kinetics by replacing dietary corn grain (CG) with soybean hulls (SH) in the presence of organic acid salts (OAS). Three total mixed rations were prepared where CG was replaced with SH at three levels (/kg DM): 0 g (Control), 75 g (SH75) or 150 g (SH150). The OAS was used at three levels (dose): 0, 5 and 10 mg/g DM of substrates. Increasing SH level increased (P < 0.05) the fractional rate of gas production (GP) and lag time. The SH75 and SH150 rations quadratically decreased (P < 0.001) the asymptotic CO2 production and the lag time of CO2 production. Moreover, the high level of OAS quadratically decreased (P 0.05) CO2 production. The OAS inclusion increased (P < 0.05) CH4 production (expressed as mL/g incubated DM and mL/g degraded DM). Increasing SH in the rations increased (P < 0.05) proportional CH4 production. Inclusion of OAS also increased proportional CH4 production. Replacing corn grain with soybean hulls could be a valuable means of sustainable mitigation of CH4 and CO2 emissions and improvement of the environmental conditions as well as provision of good feedstuff for ruminant livestock due to its in vitro fermentation characteristics. The organic acid salts did not affect ruminal gas production but decreased CO2 emissions; thus its supplementation when soybean hulls replace corn grain is perhaps redundant, though may be considered as environmental friendly way of feeding livestock

Effects of organic acid salts on ruminal biogas production and fermentation kinetics of total mixed rations with different maize silage to concentrate ratios

Methane is a major greenhouse gas (GHG) produced during the normal digestive process in ruminant animals (Blaxter and Clapperton, 1965) with a global warming potential, 25-fold that of carbon dioxide (IPCC, 2007). In addition to environmental implications, ruminant methanogenesis represents a loss of 2e12% of the gross energy intake (Johnson and Johnson, 1995; Soltanali et al., 2015) with a greater environmental impact from the confinement system compared with pasture-based system (O'Brien et al., 2012). A cow can produce 250 to 500 L of methane (CH4) per day depending on the quantity and quality of the feed which affects rate of digestion and rate of passage in the fermentation process (Johnson and Johnson, 1995). Furthermore, cattle consuming high fibre diets typically lose about 6% of gross dietary energy as methane (CH4), whereas those on high concentrate rations generally lose about 3% of dietary gross energy as CH4 (Mc Geough et al., 2012). According to the Food and Agriculture Organization of the United Nations, the livestock sector is responsible for about 18% of total global anthropogenic GHG emissionsRuminants are one of the major generators of methane, a greenhouse gas (GHG) with a global warming potential, 25-fold that of carbon dioxide. Methane production by ruminants also reduces the gross feed energy intake utilization by about 2e12%. The present study aimed to test the effects of different levels of a ruminal fermentation modulator (RFM) on in vitro ruminal fermentation and GHG production of five total mixed rations (TMR) with different silage (S) to-concentrate (C) ratios (0S:100C, 25S:75C, 50S:50C, 75S:25C, and 100S:0C). The RFM contained mainly calcium propionate and malate, and monopropylene glycol. The rumen inoculum was collected from a Brown Swiss cow fed a TMR of concentrate and alfalfa hay (1:1 dry matter (DM)) ad libitum. Gas production (GP) measurements were recorded up to 72 h of incubation. There were interactions (P 0.05) on methane production. The DM digestibility increased (linear effect; P ¼ 0.003) as silage level increased. Overall, increasing silage in the TMR lowered the asymptotic GP and DM digestibility. The asymptotic GP was higher with the addition of the RFM without any effect on fermentation kinetics. These results suggest that the RFM can be used as an environmental cleaner product in animal farming due to its ability to improve ruminal fermentation of feedstuffs and to reduce methane emission

Assessment of some browse tree leaves on gas production and sustainable mitigation of CH4 and CO2 emissions in dairy calves at different age

Rumen inoculum was collected by stomach tube from 6 young calves (Holstein, with a live weight of 40e55 kg) at 20, 40 and 60 d of age using stomach tube. Calves were fed daily one time at 11:00 h on a total local formulated mixed ration containing (/kg dry matter (DM)): 200 g canola, 625 g sorghum grains,150 g soybean meal, and 25 g mineral salts. The diet contained (/kg): 200 g crude protein, 230 g neutral detergent fiber, 50.3 g acid detergent fiber and 35.6 g either extract. The diet was formulated to cover their nutrient requirements. Calves were received 2 L of milk at 07:00 h and other 2 L at 16:00 h with a free grazing time from 8:00 to 16:00 h during the day on ryegrass and white clover ad libitum with free access to fresh water at all times during rumen contents collection phaseThe present context was aimed to determine the in vitro gas production (GP), mitigation of methane (CH4) and carbon dioxide (CO2) emission, and ruminal fermentation from nine different tree leaves as suitable alternatives for alfalfa hay. Tree leaves and alfalfa hay were incubated with rumen inoculum from calves at different ages (20, 40, and 60 d). The level of asymptomatic GP [mL/g dry matter (DM)] differed (P 0.05) was not significant by dose and substrate dose interaction. Tree leaves showed lower production of CH4 (mL/g incubated DM) and proportional CH4 emission when compared to alfalfa hay after the required period of incubation at significant level (P 0.05) on CO2 production (mL/g incubated DM and mL/g degraded DM) and proportional CO2 production. The incorporation of tested tree leaves in diet would be a valuable alternative of alfalfa hay with sustainable reduction properties of CH4 and CO2 productions. These potent tree leaves can be used as valuable cleaner product and feeding stuffs for the environment and ruminants respectively due to their in vitro fermentative properties