Oxygen deficiency can occur even in well-aerated substrates as the result of various factors. In crops grown in perlite bags, where perlite is wrapped in a polyethylene film with little surface open to the atmosphere, the dissolved oxygen concentration ([O 2 ]) may be depleted quite rapidly at high growth rates and high substrate temperatures. This situation may occur in spring cycles of greenhouse vegetable crops on the Spanish Mediterranean coast. This work studied the behaviour of a watermelon crop (Citrullus lanatus L.) grown in perlite bags in a commercial greenhouse in El Ejido (Almería). A crop irrigated with a nutrient solution super-saturated with dissolved oxygen (O 2 +) was compared with a standard irrigated crop for which the [O 2 ] in the nutrient solution was below or about saturation values (O 2 -). [O 2 ] values measured at the dripper outflow were higher for the O 2 + treatment throughout the whole crop cycle (average value of 13.5 mg L -1 ) than for the O 2 -treatment (average value of 5.9 mg L -1 ). Moreover, [O 2 ] values in the nutrient solution extracted from perlite bags at the end of the watermelon cycle were slightly higher for the O 2 + treatment during the whole diurnal period measured, and the average values were 4.5 and 3.7 mg L -1 for O 2 + and the O 2treatments, respectively. In both treatments, [O 2 ] values were above 3 mg L -1 , except for a short time interval in the O 2 -treatment. No significant differences were found between oxygen treatments for total and marketable production of watermelon, although it was slightly higher for the O 2 + treatment. Mean values of final marketable production were 7.2 and 6.9 kg m -2 for the O 2 + and O 2 -treatments respectively. Additionally, none of the quality parameters of seedless fruits were significantly affected by the nutrient solution oxygen content.
In vitro rumen biohydrogenation kinetics of mixed linoleic and alfa-linolenic acids ¤ Cinética de biohidrogenación ruminal in vitro de los ácidos linoleico y alfa-linolénico mezclados Cinética de biohidrogenação ruminal in vitro dos ácidos linoleico e alfa-linolênico misturados
Requirements for growth in the different sexes remain poorly quantified in goats. The objective of this study was to develop equations for estimating net protein (NP) and net energy (NE) for growth in Saanen goats of different sexes from 5 to 45 kg of body weight (BW). A data set from 7 comparative slaughter studies (238 individual records) of Saanen goats was used. Allometric equations were developed to determine body protein and energy contents in the empty BW (EBW) as dependent variables and EBW as the allometric predictor. Parameter estimates were obtained using a linearized (log-transformation) expression of the allometric equations using the MIXED procedure in SAS software (SAS Institute Inc., Cary, NC). The model included the random effect of the study and the fixed effects of sex (intact male, castrated male, and female; n = 94, 73, and 71, respectively), EBW, and their interactions. Net requirements for growth were estimated as the first partial derivative of the allometric equations with respect to EBW. Additionally, net requirements for growth were evaluated based on the degree of maturity. Monte Carlo techniques were used to estimate the uncertainty of the calculated net requirement values. Sex affected allometric relationships for protein and energy in Saanen goats. The allometric equation for protein content in the EBW of intact and castrated males was log protein (g) = 2.221 (±0.0224) + 1.015 (±0.0165) × log EBW (kg). For females, the relationship was log protein (g) = 2.277 (±0.0288) + 0.958 (±0.0218) × log EBW (kg). Therefore, NP for males was greater than for females. The allometric equation for the energy content in the EBW of intact males was log energy (kcal) = 2.988 (±0.0323) + 1.240 (±0.0238) × log EBW (kg); of castrated males, log energy (kcal) = 2.873 (±0.0377) + 1.359 (±0.0283) × log EBW (kg); and of females, log energy (kcal) = 2.820 (±0.0377) + 1.442 (±0.0281) × log EBW (kg). The NE of castrated males was greater than that of intact males and lower than that of females. Using degree of maturity for estimating NP and NE, we could remove the differences between sexes. These results indicate that NP and NE differ among sexes in growing Saanen goats, and this difference should be accounted for by feeding systems. Including the degree of maturity as predictor cancels out those differences across sexes in protein and energy requirements.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.