Effect of source and concentration of zinc on growth performance, meat quality and mineral retention in New Zealand rabbits

[EN] Zinc supplementation in rabbit diet favours deposition of this mineral in meat and, therefore, contributes to satisfying the daily requirements of Zn in humans that consume it. A trial was conducted to study the effect of two sources (ZnSO4 and Zn-methionate) and two concentrations of Zn, along with a control (without Zn supplementation), on weight gain, meat quality and muscle retention in New Zealand White (NZW) rabbits during fattening stage. Treatments were randomly assigned to 100 NZW rabbits 40 days old, in a completely randomised experimental design using a factorial arrangement of treatments (2×2+control). The experimental period was 30 d. In each experimental treatment, weight gain, feed consumption and meat quality were recorded, as well as the retention of Zn in serum, liver, loin and hind leg. Results showed no differences (P>0.05) in weight gain and food consumption, which can be attributed to diet-added Zn sources (ZnSO4 and Zn-methionate). Food conversion was better with the organic source at the highest concentration (P<0.05). Regarding meat quality, no differences were found (P>0.05) in hind legs for source effect and Zn concentration, while in loin, differences (P=0.02) were found in the colour parameter of L* and B* when the organic source of Zn (Zn-methionate) was supplied. Most retention of Zn on the loin occurred when a concentration of 25 mg Zn kg–1 of Zn-methionate was added, which could be important to provide larger amounts of Zn for human consumption.Luis-Chincoya, H.; Herrera-Haro, JG.; Pro-Martínez, A.; Santacruz-Varela, A.; Jerez-Salas, MP. (2021). Effect of source and concentration of zinc on growth performance, meat quality and mineral retention in New Zealand rabbits. World Rabbit Science. 29(3):151-159. http://hdl.handle.net/10251/173606OJS15115929

Comportamiento productivo e indicadores de bienestar en pollos de engorda en pastoreo

Objective: To evaluate the productive performance and welfare indicators of pastured broiler chickens. Methodology: One hundred sixty-eight straight-run broilers Ross 308 of 33 d of age were randomly assigned to two treatments: T1, confinement with ad libitum feeding and T2, system with eight hours of pasture access and concentrated feed restricted to 40% of the consumption of T1 chickens. Productive performance from 33 to 54 d of age, walking ability (Hc), latency to lie down (Lp), foot pad lesions (Qp), valgus/varus angulation (AngV), tendon breaking strength (RRTe) and tibia breaking strength (RRTi), were evaluated. Results: Productive performance between treatments was different (P < 0.05). Chickens in T1 had a higher live weight at 54 d of age (3,379 ± 39 g) than T2 (2,223 ± 39 g). Likewise, feed conversion ratio from 33 to 54 d of age was lower in confined birds (2.05 ± 0.05 g/g) than in pastured chickens (2.28 ± 0.05 g/g). These latter birds showed a better (P < 0.05) Hc and Lp, but no differences were detected between treatments (P ? 0.05) for AngV, Qp and RRTe. Implications of the study: The results are only valid for straight-run Ross 308 broiler chickens and under the specified management conditions. Conclusion: Pasture-raised broiler chickens with restricted consumption of concentrated feed, have better welfare indicators (Hc and Lp), but worse productive performance.Objetivo: Evaluar el comportamiento productivo e indicadores de bienestar de pollos de engorda en pastoreo. Metodología: Se utilizaron 168 pollos mixtos Ross 308 de 33 d de edad, que se asignaron al azar a dos tratamientos: T1, crianza en confinamiento con alimentación ad libitum y T2, sistema con ocho horas de pastoreo y ración de concentrado restringida al 40% del consumo de los pollos del T1. Se evaluó el comportamiento productivo de 33 a 54 d de edad, habilidad para caminar (Hc), latencia a postrarse (Lp), quemadura de almohadillas plantares (Qp), angulación valgus/varus (AngV), resistencia a la ruptura del tendón gastrocnemio (RRTe) y de la tibia (RRTi). Resultados: El comportamiento productivo entre tratamientos fue diferente (P < 0.05). Los pollos en T1 tuvieron mayor peso vivo a 54 d de edad (3,379 ± 39 g) que T2 (2,223 ± 39 g). Asimismo, la conversión alimenticia  de 33 a 54 d de edad fue menor en aves confinamiento (2.05 ± 0.05 g/g) que en pastoreo (2.28 ± 0.05 g/g). Estas últimas mostraron una mejor (P < 0.05) Hc y Lp, pero no se detectaron diferencias entre tratamientos (P ? 0.05) para AngV, Qp y RRTe.    Implicaciones del estudio: Los resultados obtenidos sólo son válidos para pollos de engorda mixtos Ross 308 y bajo las condiciones de manejo especificadas.   Conclusión: El pastoreo con restricción del consumo de concentrado, mejora los indicadores de bienestar Hc y Lp, pero afecta el comportamiento productivo

Duration of estrus and preovulatory surge of LH in Boer x Nubian goats synchronized with various hormones in tropical latitude of Mexico

The objective was to determine the duration of estrus, preovulatory surge of luteinizing hormone (LH), fertility and prolificacy of Boer x Nubian goats in tropical Mexico (19º29’LN) synchronized with fluorogestone acetate (FGA) and prostaglandin F2 (PGF2) combined with gonadotrophin-releasing hormone (GnRH) or equine chorionic gonadotrophin (eCG). The treatments were: T1 (FGA, n = 5), T2 (FGA + GnRH, n = 7), T3 (FGA + eCG, n = 8), T4 (PGF2 + GnRH, n = 5) and T5 (PGF2 + eCG, n = 7). The responses measured were percentage of animals showing estrus, duration of estrus (h), fertility (%), prolificacy (kids/parturition); intervals (h) from end of treatment til estrus and til peak preovulatory LH concentration, from onset of estrus til peak LH; duration of peak LH (h), and LH concentration (ng/mL). Duration of estrus was longest in goats of T3 (35.2 ± 1.4). Onset of estrus differed (P<0.05) between T2 and T3 (27.9 ± 1.2 vs. 17.2 ± 1.2). Use of PGF2 (T4 and T5) delayed onset of estrus compared with T2 and T3. Interval between sponge withdrawal and onset of LH peak was shorter in T3 than T2 (P<0.05), while that from onset of estrus to LH peak was shorter (P<0.05) with eCG, injection than with GnRH. There were no differences in length and breadth neither of the preovulatory LH surge nor in fertility or litter size (P>0.05). The use of GnRH, either with PGF2 or FGA, increased the time from onset of estrus to LH peak, whereas the use of eCG shortened it

Duration of postpartum anestrus in ewes of the Mexican high plateau

Duration of the postpartum anestrus (DPA) was studied in a typical Mexican flock using 78 ewes, Dorset x Creole and Dorset x Suffolk crosses, that lambed from September to July during the first 10 days of each month. Samples of jugular vein blood (5mL) were taken during the first 90 days postpartum, for determination of progesterone concentration until this reached a level of 1 ng.mL-1 or greater, indicating the end of estrus. The other variables analyzed were phenotype of the ewe, type of parturition (single or twins), parturition number, sex of the offspring, and month of parturition. Data were subjected to analysis of variance using a model of all fixed effects without interaction. DAP was calculated as a function of the period of year in which lambing occurred, least squares means being obtained and compared by Tukey test. Large differences were found between months of parturition (P>.0001), and three periods of year were differentiated by relative DPA, i.e. short (25.90 ± 2.65 days, from June to November); medium (46.9 ± 2.14 days in December and May); long (70.5 ± 2.27 days from January to April). The other variables analyzed did not affect DPA (P < 0.10). These results suggest that DPA varies essentially with month of lambing and that it is possible to distinguish between the minimum physiological DPA and seasoned anestrus

Inclusão de ácidos graxos poliinsaturados na dieta de ovelhas deslanadas superovuladas

In the present study, 12 pelibuey sheep, in good body condition and cycling were used. They were randomly assigned to one of two treatments: Treatment 1, sheep supplemented with avocado oil (5% of diet; T1; n=6); and Treatment 2, control sheep (no avocado oil in the diet; T2; n=6), both diets were isoprotein and isoenergetic and were offered for seven days (2 kg/animal/day). All sheep were synchronized with a progesterone-releasing intravaginal device (CIDR®), considering day 0 the insertion of the device. For sheep donor, the experimental diet began to be offered on day 5 and for both donor treatments a protocol was used with decreasing doses of the FSH hormone applying 200 mg total, starting on day 6. For both treatments, a dose of PGF2α and eCG was administered at day 7. On day 9, the CIDR® was removed and the detection of estrus began every 4 h with males equipped with aprons, and proceeded to give natural riding to the presence of heat. Seven days after mounting, embryos were collected from superovulated sheep by laparotomy, and then transferred to the recipients. At the time of washing, it was found that the ovulatory response was not very satisfactory, embryo collection was carried out only in 3 females of T1, 9 embryos were recovered and transferred, all successfully arriving at delivery. The present study showed a low ovulatory response to hormonal treatment, avocado oil supplementation showed no effects due to the poor response of females; However, good results were observed in the gestation rate, so we believe that more research is required.En el presente estudio se emplearon 12 ovejas de pelo sanas, en buena condición corporal y ciclando. Se asignaron al azar a uno de dos tratamientos: Tratamiento 1, ovejas suplementadas con aceite de aguacate (5% de la dieta; T1; n=6); y Tratamiento 2, ovejas testigo (sin aceite de aguacate en la dieta; T2; n=6), ambas dietas fueron isoproteicas e isoenergéticas y se ofrecieron durante siete días (2 kg/animal/día). Todas las hembras se sincronizaron con un dispositivo intravaginal liberador de progesterona (CIDR®), considerándose el día 0 la inserción del dispositivo. Para las hembras donadoras, la dieta experimental se comenzó a ofrecer el día 5 y para ambos tratamientos de donadoras se empleó un protocolo con dosis decrecientes de la hormona FSH aplicándose 200 mg totales, iniciando el día 6. Para ambos tratamientos, al día 7 se administró una dosis de PGF2α y de eCG. Al día 9, se retiraron los CIDR® y se inició con la detección de estros cada 4 h con machos equipados con mandil, y se procedió a dar monta natural a la presencia de celo. A los siete días posteriores de la monta, se procedió a la recolección de embriones en las hembras superovuladas mediante una laparotomía, para luego ser transferidos a las receptoras. Al momento del lavado, se encontró que la respuesta ovulatoria no fue muy satisfactoria, se procedió a realizar la recolección de embriones solo en 3 hembras del T1, se recuperaron 9 embriones y fueron transferidos, llegando con éxito todos al parto. El presente estudio mostró una respuesta ovulatoria baja al tratamiento hormonal, la suplementación de aceite de aguacate no mostró efectos por la poca respuesta de las hembras; sin embargo, se observaron buenos resultados en la tasa de gestación, por lo cual consideramos que se requiere mayor investigación.No presente estudo foram utilizadas 12 ovelhas pelibuey, hígidas, em bom estado corporal e ciclando. Eles foram distribuídos aleatoriamente em um dos dois tratamentos: Tratamento 1, ovinos suplementados com óleo de abacate (5% da dieta; T1; n=6); e Tratamento 2, ovelhas controle (sem óleo de abacate na dieta; T2; n=6), ambas as dietas foram oferecidas por sete dias (2 kg/animal/dia). Todas as fêmeas foram sincronizadas com dispositivo intravaginal liberador de progesterona (CIDR®), considerando o dia 0 a inserção do dispositivo. Para as fêmeas doadoras, a dieta experimental passou a ser oferecida no dia 5 e para ambos os tratamentos de doadoras foi utilizado um protocolo com doses decrescentes do hormônio FSH, aplicando um total de 200 mg, iniciando no dia 6. Para ambos os tratamentos, no dia 7 o administrado uma dose de PGF2α e eCG. No dia 9, os CIDR® foram removidos e a detecção de estro começou a cada 4 horas com os machos equipados com avental, e a monta natural foi realizada na presença de cio. Sete dias após a cobertura, foram coletados embriões das fêmeas superovuladas por meio de laparotomia, para posterior transferência para as receptoras. No momento da lavagem, verificou-se que a resposta ovulatória não foi muito satisfatória, foi realizada coleta de embriões apenas em 3 fêmeas T1, 9 embriões foram recuperados e transferidos, todos chegando ao parto com sucesso. O presente estudo mostrou uma baixa resposta ovulatória ao tratamento hormonal, a suplementação com óleo de abacate não apresentou efeitos devido à baixa resposta das fêmeas; no entanto, foram observados bons resultados na taxa de prenhez, pelo que consideramos que são necessárias mais pesquisas

Suckling, male effect and kisspeptin in the reproductive management of ewes in postpartum anestrus

Objective: To describe the management strategies of controlled suckling and the male effect to reduce postpartum anestrus, and to show the participation of kisspeptin to regulate the effect of both factors. Design/Methodology/Approach: A review of scientific publications was conducted, in order to show the importance of suckling and the male effect as strategies to reduce postpartum anestrus in the ewe, as well as the relation of kisspeptin with both factors. Results: Seasonal anestrus can be avoided with the use of breeds adapted to the local environment, such as Pelibuey. Postpartum anestrus occurs mainly as a result of suckling, since the latter inhibits the pulsating secretion of the gonadotropin-releasing hormone (GnRH) and the luteinizing hormone (LH). The exact path of this inhibition is unknown, although it seems that endogenous opioid peptides and kisspeptin are intermediaries. Controlled suckling and the male effect are management strategies that improve the reproductive behavior of postpartum ewes. Kisspeptin regulates the influence of the male effect through the secretion of GnRH/LH. Study Limitations/Implications: To understand the impacts of suckling and the male effect on the duration of postpartum anestrus, as well as the participation of kisspeptin in the regulation of both effects, will allow designing management strategies to improve the reproductive efficiency of the ewes. Findings/Conclusions: Controlled suckling and the male effect reduce postpartum anestrus and improve the reproductive behavior of the ewes; advancing knowledge of the kisspeptin effect could improve the effectiveness of both techniques

Caracterización del sistema de producción avícola de traspatio en el Estado de Campeche, México.

A study was conducted to characterize the backyard chicken production system in Campeche State, Mexico, as the basis of a program for utilizing local poultry genetic resources. A total of 260 surveys were administered in person. The parents undertake backyard production activities. Farmers have, on average, 0.20 ± 0.1 hectares for raising local chickens (LC). Flock size was 24.4 ± 1.3 birds per household. The number of egg/hen/year was 45.8 ± 1.6. Confined and semi-confined production systems are used. Farmers fed chickens with corn, whereas chicks were fed with commercial feed. During the rainy season, flu and diarrheal diseases are more frequently observed. Body size is the main trait for acquiring/selecting breeders within/outside the flock. Selection of eggs for incubation is based on size and freshness. Feed shortages, diseases, predators, and lack of technical assistance services were the major constraints for LC backyard production. In conclusion, backyard chicken production based on LC provides a readily available source of animal protein and cash income for households in Campeche State, Mexico.Se realizó un estudio con el objetivo de caracterizar la producción avícola de traspatio en el estado de Campeche, México, como el inicio de un programa para la utilización de los recursos genéticos avícolas locales. Se encuestó a un total de 260 productores. Las actividades productivas de traspatio las realizan los padres. Los productores destinan un promedio de 0.20 ± 0.1 hectáreas para la cría de pollos locales (PL). El tamaño de la parvada fue de 24.4 ± 1.3 aves por hogar. El número de huevos/gallina/año fue de 45.8 ± 1.6. Se utiliza tanto el sistema de producción en confinamiento como en semi-confinamiento. Las aves son alimentadas con maíz, excepto los pollitos, que son alimentados con alimento balanceado comercial. Durante la época de lluvias se observan con mayor frecuencia problemas de diarrea y enfermedades respiratorias. El peso corporal es la principal característica por la que las aves reproductoras son seleccionadas dentro y fuera de la parvada. Los huevos destinados a incubación son elegidos con base en su tamaño y el número de días transcurridos desde que son puestos. La producción avícola de traspatio tiene como principales limitantes la falta de alimento para los animales, las enfermedades, los depredadores y la falta de asistencia técnica. En conclusión, la producción avícola de traspatio, basada en animales locales, provee de una fuente fácilmente disponible de proteína de origen animal e ingresos económicos a los hogares del estado de Campeche, México

Fec, CA5A and CLSTN2 genes and their function during sheep ovulation: a review.

Objective: To describe the function of Fec, CA5A and CLSTN2 genes during ovulation in ewes. Design/methodology/approach: A search and analysis of scientific information related to Fec, CA5A and CLSTN2 genes in sheep was performed. Results: Fec, CA5A and CLSTN2 genes are involved at the ovarian level; ewes carrying the first gene were found to have increased ovulation rate, folliculogenesis and granulosa cell differentiation. CA5A stimulates an increased follicular rate and plays an important role in pre-implantation. While CLSTN2 has activity in ovarian development and growth; it also has the ability to interact with other genes involved in follicular maturation, granulosa cell differentiation and development of the ovarian follicle. Limitations on study/implications: Ewes carrying these genes increase the prolificacy rate in the flock. Findings/conclusions: The expression of these genes acts synergistically in the ovulatory process, enhancing the ovulatory response by contributing to endocrine, paracrine and molecular synchronisation, so that the maturation of the oocyte occurs, leading to ovulation

Evaluation of two soybean soapstocks in egg production and quality in Bovans hens

En la alimentación de gallinas en postura se utiliza el aceite crudo de soya (ACS), pero debido a que éste compite con la alimentación humana su precio es alto, por lo cual se evaluaron dos aceites acidulados de soya (AAS), los cuales son más económicos. El objetivo del estudio fue evaluar el efecto de los AAS en la producción de gallinas Bovans, calidad de huevo, composición lipídica y costo de un kilo de huevo. Se determinó la energía metabolizable (EM) y composición de lípidos de los acidulados. Se utilizaron 240 gallinas en seis tratamientos, con cinco repeticiones, con ocho gallinas cada una. En las dietas se incluyeron ACS y dos acidulados (AAST y AASY), a dos niveles (2% y 4%). Las variables productivas fueron alimento consumido, porcentaje de postura, peso del huevo, masa del huevo, conversión alimenticia; en calidad de huevo se midió altura de albumina, unidades Haugh (UH), color de yema y grosor de cascarón. Se determinó la composición lipídica del huevo y su costo. Al sustituir el ACS por los AAS no se afectó la producción de las aves (P>0.05). En calidad de huevo, los AAS mejoraron las UH (P0.05), but did improve Haugh unit values (P<0.05). Egg fatty acids composition changed in response to oil composition (P<0.05), and inclusion concentration affected the levels of specific fatty acids. Use of the soapstocks resulted in a lower cost per kilogram of eggs than with CSO (P<0.05). Substitution of crude soy oil with the evaluated soapstocks had no effect on productive variables, improved egg quality and lowered overall feed costs

Productive performance of rabbits fed alfalfa (Medicago sativa)- or white clover (Trifolium repens)- based diets

Objective: To evaluate the productive performance of rabbits fed diets based on white clover and alfalfa. Design/methodology/approach: Rabbits have the ability to consume high fiber diets, therefore, one diet based on white clover (Diet 1) and another based on alfalfa (Diet 2), were studied. The experiment was carried out during the Autumn-Winter season of 2018. A total of 111 rabbits (males and females), weaned at 31 days of age, were used. The diets were randomly assigned to 20 cages, four to six animals each: 56 rabbits received Diet 1 and 55 received Diet 2. All the animals were offered feed and water ad libitum during the 35 days of growth. The response variables registered weekly were: live weight (LW), daily weight gain (DWG) and feed conversion (FC). At 67 days of age, hot (HCY) and cold (CCY) carcass yields were determined. Results: At the end of the growth period (31 to 66 days of age) the following results were obtained for diets 1 and 2 in such order, LW: 2012±36 and 1960±37 g, DWG: 32.2±1.57 and 28.4±1.60 g/animal, FC: 3.3±0.2 and 3.4±0.2 g/g, HCY: 48.0±0.5 and 55.9±0.6% and CCY: 48.1±0.5 and 55.8±0.7%. Limitations/implications: Because no differences (P?0.05) were detected between diets, with all the response variables, more studies are needed to better know these legumes. Findings/conclusions: White clover may completely replace alfalfa in rabbit diets.Objective: Evaluate the productive performance of rabbits fed alfalfa- and white clover-based diets.Design/ methodology/ approach: Rabbits can consume high-fiber diets. Therefore,this study evaluated a white clover-based diet (Diet 1) and an alfalfa-based diet (Diet 2).The experiment was carried out during the Fall-Winter season of 2018. This study used111 rabbits (males and females), weaned at 31 days of age. Diets were randomlyassigned to 20 cages, four to six animals per cage. In total, 56 rabbits received Diet 1and 55 Diet 2. All animals had free access to feed and water during the 35-day growthperiod. The weekly recorded response variables were live weight (LW), daily weight gain(DWG), and feed conversion (FC). At 67 days of age, hot carcass yield (HCY) and coldcarcass yield (CCY) were determined.Results: At the end of the fattening period (31 to 66 days of age), there were nosignificant differences between the two experimental groups. The results for Diet 1 and2, respectively, were the following: LW = 2012±36 and 1960±37 g, DWG = 32.2±1.572and 28.4±1.60 g/animal, FC = 3.3±0.2 and 3.4±0.2 g/g, HCY = 48.0±0.5 and 55.9±0.6%,and CCY = 48.1±0.5 and 55.8±0.7%.Limitations/ implications: Due to the lack of significant differences (P?0.05), furtherstudies are required to better understand these legumes.Findings/ conclusions: White clover could completely replace alfalfa in rabbit diets