María Lábaque

Effects of thymol and carvacrol feed supplementation on lipid oxidation in broiler meat

Poultry meat is particularly prone to oxidative deterioration due to its high concentration of polyunsaturated fatty acids. The present study evaluates the effects of thymol and its isomer carvacrol on lipid oxidation when supplemented to the feed. Supplementation with the antioxidant butylated hydroxytoluene was used as a positive control. Thus, broiler chickens were assigned to 1 of 4 treatments: vehicle (control), 150 mg/kg of butylated hydroxytoluene (positive control), 150 mg/kg of thymol, or 150 mg/kg of carvacrol. Breast and thigh samples were taken at 0, 5, and 10 d of 4 degrees C storage. Lipid oxidation was determined by the analysis of 2-TBA reactive substances (TBARS). Sample storage for 5 to 10 d significantly increased the levels of TBARS. Feed supplementation did not significantly affect breast sample oxidation. However, after 5 and 10 d of storage, increasingly higher values of TBARS were detected in thigh samples of the control group in comparison to the 3 supplemented groups. Interestingly, the same lower values of TBARS were detected between those feed-supplemented groups. Therefore, the application of the natural antioxidants thymol or carvacrol could be useful to improve poultry meat quality.

Effects of thymol and isoeugenol feed supplementation on quail adult performance, egg characteristics and hatching success

1. A study was conducted to evaluate whether feed supplementation with thymol or isoeugenol can alter Japanese quail growth rate and final body weight, the female onset of puberty, hen-day egg production and the physical and chemical characteristics of the egg, as well as its potential to alter hatchability. 2. From 4 to 16 weeks of age, birds from each cage (1 male: 3 females) were assigned to 1 of 3 treatments that differed in the supplement added to the feed: control, thymol or isoeugenol (400 mg/kg). The average ages (d) at first egg lay (FIRST), at 25% egg production (A25% EP), at 50% egg production (A50% EP) and weekly and cumulative hen-day egg production (HDEP) were calculated. In addition, physical and chemical characteristics of the eggs, their fertility and hatchability were also evaluated for each group. 3. Feed supplementation did not significantly affect growth rate, final body weight, egg production parameters, fertility and physical characteristics of egg or most of the fatty acid components of the yolk. 4. The group treated with isoeugenol showed an increase in the percentage of palmitoleic fatty acid compared to the control, with thymol group showing intermediates values. 5. Both thymol and isoeugenol supplemented groups showed increased hatchabilities, by 18·8% and 11·8%, respectively, compared to their control counterparts. 6. The improvement in the hatching success of the eggs from the thymol and isoeugenol supplemented groups without a negative impact on their performance may have important economic implications for future breeding programmes, particularly if these effects generalise from quail to other more commercially important poultry species, such as chickens or turkeys.

Thymol as natural antioxidant additive for poultry feed: oxidative stability improvement

ABSTRACT Antioxidant are regularly included in poultry feed as protection from deterioration during storage. Recently the interest for the use of natural phytochemicals in animal diets has been increased. Thymol (THY) has been proven to be an effective antioxidant for extending broiler meat quality during storage with similar action to the widely used butylated hydroxytoluene (BHT). This study evaluates whether THY can also have a protective effect on the feed mash by assessing its antioxidant potential and related changes in fatty acid (FA) balance. Feed mash was assigned to 1 of 4 treatments, control (CON, no additive), vehicle (VEH, ethanol 96%), BHT (400 mg BHT /kg feed) and THY (400 mg THY /kg feed). Three replicates of each treatment were taken after 0, 30, and 60 d of storage at room temperature (23 ± 3°C) and relative humidity (40 ± 5%). Peroxide value (PV), titratable acidity (TA) and FA relative composition were determined. As expected, there were no treatment effects on those variables at 0 d of storage. However, higher PV values were detected in the CON and VEH groups after 30 and 60 d of storage in comparison to the THY and BHT treated samples (CON = VEH > THY = BHT). While a slight increase was also observed in TA through storage time, no particular treatment effects were detected. Relative FA composition changed with storage time only in the CON and VEH group which had a decrease in polyunsaturated fatty acids and an increase in saturated FA. No changes were detected in the Thy and BHT treated feeds. The results suggest a similar THY and BHT protective effect on feed mash lipid oxidation. Thus, THY could be considered as a useful natural alternative to help sustain quality of poultry feed.

Thymol detection and quantitation by solid-phase microextraction in faeces and egg yolk of Japanese quail

To measure bioavailability of the active ingredients of phytogenic feed additives in poultry products and subproducts is a key element for developing a rational understanding of its mode of action and biological effects. Hence, we validated a headspace solid phase microextraction (HS-SPME) technique followed by gas chromatography-mass spectrometry as an analytical extraction procedure and as method for detection and quantitation of 2-Isopropyl-5-methylphenol (thymol) in faeces and egg yolk of quail. The suitability of this method for thymol analysis in both matrices was first proved via linearity, limit of detection, limit of quantification, and recovery using m-cresol as internal standard. The optimal HS-SPME extraction conditions were obtained at 40°C for 5min in faeces and 60°C for 30min in egg yolk. This procedure was found to be precise, sensitive and linear in the range of 2.5-100ng/gr for faeces and 20-800ng/gr for the egg yolk. Limits of detection were 0.5ng/g and 5ng/g for faeces and yolk, respectively, and the limits of quantitation were 1ng/g and 10ng/g for faeces and yolk, respectively. The method was successfully used for measuring thymol in fecal and egg yolk samples, from quails supplemented with thymol in their diets. Thus, in fresh faeces and egg yolk samples obtained from a supplemented group (80mg thymol per bird per day) were determined as 31.51ng/g for faeces and 11.83ng/g for the egg yolk.

Ontogeny of copulatory behaviour in male Japanese quail classified by their T-maze performance as hatchlings.

1. This study examines the time courses of male mating behaviours using quail that were categorised at 2 d of age as high performance (HP) or low performance (LP) individuals in a T-maze. 2. Individually caged males from each T-maze category were observed for 5 min after a female of the same category (HP or LP) was introduced into their home cages as a sexual partner at 4, 5, 6, 8, 10 and 12 weeks of age. The number of grabs, mounts and cloacal contacts performed by each male and his copulatory efficiency (number of cloacal contacts/number of grabs; CE) were determined at each time interval. 3. No differences were observed in the proportion of HP and LP males performing grabs at any of the ages evaluated. However, a greater proportion of HP males showed mounting and cloacal contact behaviour, coupled with a higher CE than did their LP counterparts at 5 and 6, 6 and 8, and 8 weeks of age, respectively. At those ages, a higher mean number of mounts and cloacal contacts were also observed. No significant sexual behaviour differences between HP and LP quail were observed at 10 and 12 weeks of age. 4. The results suggest that rapid negotiation of the T-maze in hatchlings is associated with accelerated puberty in male quail. The differential reproductive behaviour of HP males during the development of puberty does not remain extant in fully developed quail. 5. The finding of accelerated male developmental sexual activity responses in HP quail indicates that selection for T-maze HP behaviour may allow males to be successfully bred at an earlier age.

Thymol feed supplementation in quail alters the percentages of nutritionally relevant egg yolk fatty acids: effects throughout incubation†

BACKGROUND Polyunsaturated fatty acids (PUFA) are crucial components of egg yolk and particularly prone to oxidative damage, generating losses of nutrients for embryonic development and influencing the quality of eggs for human consumption. The aim of this study was to evaluate whether dietary thymol (a natural antioxidant) is related to changes in quail egg yolk total (T), triglyceride (TG) and phospholipid (PL) fatty acid composition at different stages of embryo development. Thus female Japanese quail (100 days of age) were assigned to one of two dietary treatments (12 individuals each): CON (basal diet) or THY (0.0016 mol thymol day-1 per bird). After 2 weeks of supplementation, eggs were incubated and samples were obtained at 0, 4 and 16 days of embryonic development. RESULTS In 0 day THY eggs, α-linolenic acid and n-3 PUFA in T and TG, docosahexaenoic acid and PUFA in T and arachidonic acid in TG were increased, while saturated fatty acids (SFA) in T were reduced. From 4 days on, PUFA, n-3 PUFA and SFA from T and TG in THY eggs were found to be similar to those of CON eggs. The changes in PL throughout incubation were similar in both dietary treatments. CONCLUSION Thymol would provide the embryo with PUFA for synthesis/deposition in membranes and/or assign to supply energy. Additionally, thymol supplementation would be advisable for the production of healthier table eggs.

Insights into thermal stress in Japanese quail (Coturnix coturnix): dynamics of immunoendocrine and biochemical responses during and after chronic exposure

Abstract Avian require comfortable temperatures for optimal development and heat stress is a high concern in warm weather countries. We aimed to assess the dynamics of immunoendocrine and biochemical variables responses of birds exposed to a heat stressor applied during daylight hours, during the chronic stress and the recovery periods. We hypothesize that variables involved in the birds response will be differentially and gradually modified during those periods. Female quail (n = 210) were housed in six rearing boxes. At 29 days of age, the temperature in three boxes was increased from 24 to 34 °C during the light period throughout the nine days (Stress Treatment). The other three boxes remained at 24 °C and were used as controls. The subsequent 12 days were considered as recovery period. Different sets of 12 birds/treatment were blood-sampled at 29 (basal), 32, 35, 38 (stress), 41, 44, 47, and 50 (recovery) days of age, respectively. Immunoendocrine (corticosterone, lymphoproliferation, heterophil/lymphocyte ratio (H/L), and antibody response) and biochemical (glucose, total proteins, globulins, and albumin) variables were assessed. During stress, progressive corticosterone and H/L increments, and antibody titers and lymphoproliferation decreases were detected. No clear pattern of changes was found in biochemical variables. During recovery, while corticosterone and lymphoproliferation had recovered three days after the stressor ended, H/L and antibody responses required respectively nine and 12 days to recover to their basal levels, respectively. Findings suggest that immunity is already threatened when heat stress is sustained for three or more days. However, the system appears resilient, needing six to 12 days to recover to their basal responses.

Hydrology and Hydraulics of the Suquía River Basin

The Suquia River Basin is regulated by the San Roque Dam, which is located in its upper basin. With a basin area of over 1,750 km2 and a mean streamflow of 9.8 m3 s−1, the Suquia is the second river of the Province of Cordoba (Argentina), according to its streamflow. Downstream from the dam, the river, in its middle basin, runs across a mountain area and then through the city of Cordoba. After leaving the city, in its lower basin, it flows for approximately 150 km towards the northeast until its mouth in the Mar Chiquita Lake. Therefore, the Suquia River has an endorheic basin. The San Roque Dam was designed as a multipurpose dam, and its priority uses include flood mitigation, water supply, irrigation and power generation. On its journey through the city of Cordoba, the Suquia River is urbanised with bridges, fords, coastal roads and a flood plain that is used for recreational purposes. Several studies were conducted to estimate extreme basin events. The basin characteristics were determined by both conventional methods and hydrological modelling. The maximum rainfall records arose from the frequency analysis of 21 rainfall stations installed along the basin.