The Opuntia effect upon the out-of-season embryo implantation rate in goats: Corpus luteal number, corpus luteal diameter and serum progesterone concentrations

Abstract

We evaluated the possible effect of targeted supplementation of protein enriched Opuntia megacantha Salm-Dyck cladodes, the flat leaf-like stem of cactus species, upon corpus luteum number (CLN), corpus luteum diameter (CLD), serum progesterone concentrations (P4) and embryo implantation rate (EIMPL) in anestrous goats exposed to sexually active males. During the non-breeding season (May-Jun, 25°LN), anestrus Alpine-Saanen-Nubian × Criollo adult goats (n = 45) homogeneous regarding live weight (LW, kg) and body condition score (BCS, units) were randomly assigned to the supplement treatments: 1). Protein-enriched Opuntia (PEO;n = 15; 43.8 ± 1.5 kg LW, 2.48 ± 0.10 BCS; 29.8% CP, 2.2 Mcal ME kg−1), 2). Non-enriched Opuntia (NEO; n = 15; 43.8 ± 1.5 kg LW, 2.47 ± 0.10 units BCS; 6.4% CP, 2.1 Mcal ME kg−1), compared with 3). Control (CONT; n = 15; 45.41 ± 1.5 kg LW, 2.54 ± 0.10 units BCS). Both NEO and PEO goats were individually supplemented with cladodes (160 g d−1; 0900–1000 h) and then goats grazed in a marginal rangeland (1000–1800 h). PEO was bio-fortified in a fermentation bioreactor (1% of Scaromices cereveciae, + 1% urea + 0.1% of ammonium sulphate). Three transrectal ultrasonographic scans (US) were performed during the supplement adaptation period (20d) to confirm the goat´s anovulatory status and then (May 20) exposed to males during a 10d breeding period. A 4th-US quantified CLN and CLD 20 d post-male introduction (PMI), while a 5th-US evaluated EIMPL (47 d, PMI); supplementation lasted up to June 30. No differences (P > 0.05) in LW and BCS occurred either at the onset (44.38 ± 1.5 kg, 2.49 ± 0.10 units) or at the end (45.03 ± 1.5 kg, 2.60 ± 0.20 units) of the experiment, neither concerning P4-average (3.73 ± 1.6 ng mL−1) nor related to the treatment x time interaction. Although no differences in the reproductive response (P > 0.05) regarding CLN, CLD and EIMPL occurred in the PEO and NEO, an amplified response (P < 0.05) was observed in the PEO-group compared to the CONT goats [CLN: 1.33, 0.71 & 0.43 ± 0.7 units; CLD: 1.66, 0.92 & 0.61 ± 0.30 mm; and EIMPL: 86, 53 & 18 ± 14%, respectively]. Targeted supplementation with protein-enriched Opuntia cladodes (i.e. the “Opuntia Effect”) during the conception-to-implantation period to anestrous goats exposed to males increased out-of-season reproductive outcomes; this strategy could be potentially important to uphold the sustainability of goat production systems under semiarid conditions.