To signal or not to signal? Chemical communication by urine-borne signals mirrors sexual conflict in crayfish

Background: Sexual selection theory predicts that females, being the limiting sex, invest less in courtship signals than males. However, when chemical signals are involved it is often the female that initiates mating by producing stimuli that inform about sex and/or receptivity. This apparent contradiction has been discussed in the literature as 'the female pheromone fallacy'. Because the release of chemical stimuli may not have evolved to elicit the male's courtship response, whether these female stimuli represent signals remains an open question. Using techniques to visualise and block release of urine, we studied the role of urine signals during fighting and mating interactions of crayfish (Pacifastacus leniusculus). Test individuals were blindfolded to exclude visual disturbance from dye release and artificial urine introduction. Results: Staged female-male pairings during the reproductive season often resulted in male mating attempts. Blocking female urine release in such pairings prevented any male courtship behaviour. Artificial introduction of female urine re-established male mating attempts. Urine visualisation showed that female urine release coincides with aggressive behaviours but not with female submissive behaviour in reproductive interactions as well as in intersexual and intrasexual fights. In reproductive interactions, females predominately released urine during precopulatory aggression; males subsequently released significantly less urine during mating than in fights. Conclusions: Urine-blocking experiments demonstrate that female urine contains sex-specific components that elicit male mating behaviour. The coincidence of chemical signalling and aggressive behaviour in both females and males suggests that urine release has evolved as an aggressive signal in both sexes of crayfish. By limiting urine release to aggressive behaviours in reproductive interactions females challenge their potential mating partners at the same time as they trigger a sexual response. These double messages should favour stronger males that are able to overcome the resistance of the female. We conclude that the difference between the sexes in disclosing urine-borne information reflects their conflicting interests in reproduction. Males discontinue aggressive urine signalling in order to increase their chances of mating. Females resume urine signalling in connection with aggressive behaviour, potentially repelling low quality or sexually inactive males while favouring reproduction with high quality males

Effects of Field Pea Supplementation on Digestibility and Rumen Volatile Fatty Acid Concentration of Diets Containing High and Low Quality Forages

Five ruminally cannulated steers were used to evaluate the effects of supplementation (no supplement, field peas, or dry rolled corn; 0.43% BW) with high and low quality forages on diet digestibility and rumen volatile fatty acid concentrations. Th e inclusion of field peas increased dry matter intake and organic matter digestibility over dry rolled corn and unsupplemented steers. Propionate proportions were less for field peas and control treatments than dry rolled corn, while acetate proportions increased in field peas, and control treatments as compared to dry rolled corn. As a result, acetate to propionate ratio was reduced when dry rolled corn was supplemented. Inclusion of field peas alters the volatile fatty acid concentrations, increases dry matter intake, and improves organic matter digestibility when supplemented to forage fed steers

Effect of Harvest Method and Ammoniation on Digestibility and Intake of Corn Residue

The effects of three harvest methods, both with and without ammonia treatment, on the in vivo digestibility and intake of baled corn residue were assessed in a digestion trial with lambs. Treatments included three corn residue harvest methods (conventional rake and bale, New Holland Cornrower™ with eight rows or with two rows of corn stalks chopped into the windrow containing the tailings [leaf, husk and upper stalk] from eight harvested rows) and the effects of ammoniation at 5.5% of DM compared to no ammoniation of the residue. Th e 2- Row baled residue (51.7%) had greater dry matter digestibility than both 8- Row (47.3%) and CONV (44.7%). Ammoniation increased dry matter digestibility by 24% (10 percentage units) across all residue types. Additionally, ammoniation increased intake. Utilizing alternative harvesting technologies and ammoniation can improve the digestibility of baled residue. These effects are additive and combining the two technologies resulted in the greatest improvement in digestibility

Effect of Corn Residue Harvest Method on In Vivo and In Vitro Digestibility

A digestion study was conducted using 18 crossbred wether lambs to evaluate the effects of corn residue harvesting method and ensiling on the digestibility of corn residue. Husks had the greatest digestibility compared to any of the harvesting methods. No differences were observed for the digestibility of husklage, ensiled husklage, or stalklage. None of the harvest methods resulted in residue digestibilities similar to husks

Uses of Fabry-Perot Velocimeters in Studies of High Explosives Detonation

The Fabry Perot has become an important and valuable tool by which explosive performance information can be obtained relatively easily and inexpensively. Principle uses of the Fabry Perot have been free surface, and particle velocity measurements in one dimensional studies of explosive performance. In the cylinder test, it has been very useful to resolve early wall motions. We have refined methods of characterizing new explosives i.e. equation of state, C-J pressure, via the cylinder shot, flat plate, and particle velocity techniques. All of these use Fabry Perot as one of the principle diagnostics. Each of these experimental techniques are discussed briefly and some of the results obtained. Modeling developed to fit Fabry-Perot results are described along with future testing

Impact of Corn Silage Inclusion on Nutrient Digestion and Rumen Fermentation in Finishing Cattle

A digestion study was conducted comparing different inclusions of corn silage used as a roughage source on digestibility, feeding behavior and rumen environment. Treatments consisted of 3 inclusions of corn silage at 0, 7.5 and 15% of the diet DM, and a control treatment with 7.5% alfalfa. As expected, increasing available energy and decreasing roughage (either silage or alfalfa) showed an increase in diet digestibility and ruminal propionate concentrations. However, average ruminal pH was least, with more time spent in subacute acidosis (pH \u3c 5.3) when cattle were fed no roughage. These data suggest that feeding cattle increasing silage inclusions as a roughage source prevented ruminal conditions from entering and remaining in subacute acidosis. Feeding corn silage at 15% gave similar digestibility responses compared to 7.5% alfalfa. Including silage as a roughage source at 15% could help prevent acidosis and digestive upset in feedlot cattle

Effects of Isolated Nutrients in Distillers Grains on Total Tract Digestibility and Digestible Energy in Forage Diets

A digestion study was conducted to evaluate the contribution of individual nutrient components of distillers grains on nutrient digestibility and digestible energy. All diets contained 56% brome hay with a control diet containing either 40% corn; or 40% modified distillers grains. Four additional diets compared the contribution of fat, protein, fiber, and solubles components of distillers grains. No differences were observed for digestibility of DM, OM, and NDF among treatments. Feeding the isolated protein resulted in similar digestible energy to modified distillers grains, suggesting the bypass protein component contributes heavily to energy in distillers

Soluble CD200 Correlates With Interleukin-6 Levels in Sera of COPD Patients: Potential Implication of the CD200/CD200R Axis in the Disease Course

BACKGROUND: COPD represents a multifactorial lung disorder with high morbidity and mortality. Despite intensive research concerning the underlying disease mechanisms, the involvement of the CD200/CD200R axis in supporting or preventing the onset of COPD has not yet been addressed. Since the CD200/CD200R axis is crucially implicated in the maintenance of pulmonary immune homeostasis, we hypothesized that it might be involved in controlling the onset of COPD. METHODS: To address this, we analyzed the serum samples from COPD patients and normal controls for soluble (s) CD200 and correlated the data to COPD-relevant clinical parameters. In addition, basic studies were conducted in CD200-deficient and wild-type mice in which COPD-like inflammation was induced with elastase/LPS followed by lung and serum component analysis. RESULTS: We observed a positive correlation between serum sCD200 and IL-6 levels as well as a trend toward a negative correlation of sCD200 with vitamin D3 in COPD patients. Further investigations in mice revealed that despite elevated serum concentration of MMP-9 in CD200KO mice, the early onset of COPD-like lung inflammation was similar in CD200-deficient and wild-type animals in terms of immune cell infiltration, emphysematous changes, and mucus overproduction. CONCLUSIONS: While our murine studies suggest that the co-inhibitory molecule CD200 does not appear to play a prominent role in the early onset of COPD-like features, correlation of sCD200 serum levels with COPD-related parameters in humans with established disease revealed that the CD200/CD200R axis may be mechanistically linked to the disease course in COPD patients

Site and Extent of Digestion of Finishing Diets Containing Syngenta Enhanced Feed Corn

Four ruminally and duodenally fistulated steers were utilized to evaluate the effects of Syngenta Enhanced Feed Corn™ containing an alpha amylase enzyme trait (SYT- EFC) compared to the isoline parental control corn without the alpha amylase enzyme trait (Negative Isoline) on site and extent of digestion in finishing diets. Cattle fed SYT- EFC dry rolled corn had numerically greater postruminal starch digestibility, excreted lower fecal starch, and had greater total tract starch digestibility compared to cattle fed Negative Isoline corn. These data would suggest that cattle are able to utilize more starch from corn containing the SYT- EFC trait, which has resulted in greater gains and efficiencies

Evaluation of the Energy Value and Nutrient Digestibility of Distillers Grains That Have Undergone a Fiber Separation Process in Finishing Diets

A digestion study was conducted to determine the effects of feeding a new, high protein distillers grains and corn bran plus solubles on nutrient digestibility. Treatments included a corn-based control, high protein distillers at both 20% and 40%, corn bran plus solubles, traditional wet distillers grains and traditional dry distillers grains all at 40% of diet DM. Feeding high protein distillers grains or corn bran plus solubles resulted in decreased digestibility compared to corn or traditional wet and dry distillers grains, but increased energy intake. Traditional wet and dry distillers grains also resulted in decreased digestibilities while energy intake was increased. Volatile fatty acid profiles and pH parameters were not different across treatments. Overall, nutrient digestibility for high protein distillers grains and corn bran plus solubles is similar to traditional wet or dry distillers grains