Vegetable biocholine supplementation in lambs during the feed transition period improves health and enhances weight gain

Highlights

• Peri-weaning period of dairy lambs is considered critical.

• Vegetable biocholine (VB) supplementation improves lamb performance.

• Free radicals and lipid peroxidation decrease in lambs that consume VB.

• Antioxidant stimulation is observed in lambs supplemented with VB.

Abstract

Lambs born from dairy ewes are removed from their mothers within hours of ingesting colostrum; this influences their growth and development, especially when artificial milk has poor quality or insufficient volume. Alternatives have been proposed to assist lambs during this phase, including providing concentrate with additives such as choline, which is involved in various physiological processes. This study's objective was to determine the effects of vegetable biocholine (VB) supplementation on growth, biochemistry, and antioxidant responses in lambs from dairy ewes during the feed transition period. We used 40 Lacaune lambs in a randomized block design, distributed in four groups with five replications (two animals per replication). VB was added to the concentrate and was consumed between 30 days pre-weaning to 30 days post-weaning (total 60 days). The treatments were as follows: T0, without added VB, control group; T2, 2 g VB per animal/day; T4, 4 g VB per animal/day; and T6, 6 g VB per animal/day. The weight gain increased in T2, T4, and T6 lambs when compared to T0. Using orthogonal polynomials analysis suggested that the ideal supplementation dose is 2.81 g/day per animal when considering the maximum average daily gain (ADG), which corresponds to 0.189 g VB/kg of body weight (BW). After weaning, there were lower serum concentrations of creatine kinase enzyme in lambs supplemented with VB than in controls. No differences were observed concerning levels of total protein, albumin, or globulins. Alanine aminotransferase (ALT) activity of T2 and T4 lambs was greater only at weaning (30 days). Glucose was greater in T2 and T4 lambs only on day 15. In general, VB supplementation decreased serum levels of reactive oxygen species (ROS) from day 15 of supplementation; these animals had lower lipid peroxidation levels after weaning. The activities of glutathione S-transferase (GST) did not differ. These data suggest that supplementation with VB increases weight gain and improves health, primarily by reducing free radical levels during the dietary transition period.

Introduction

The Lacaune breed has a dual purpose: breeders are directed to milk production, while their (male) offspring are used for meat production (Barillet et al., 2001; Figueira et al., 2018). The rearing phase of lambs is a critical period for production because newborns are separated from their mothers a few hours after birth (Monteiro et al., 2014). Lambs that do not receive nutritional alternatives to fill the breast milk deficit suffer high mortality rates during the first weeks of life (Silva et al., 2010). In general, greater weight gain is correlated with lower mortality rates; therefore, it is necessary to offer the best environment and nutrition conditions to avoid losses during this period, even though lambs are capable of compensatory weight gain (Villas Bôas et al., 2003; Rosa et al., 2017).

Dairy farms adopt weaning systems after colostrum ingestion, and they offer artificial feeding up to 45–60 days. The evidence suggests that body condition at weaning is more important than age in enhancing performance in future phases of lambs (Monteiro et al., 2014). Therefore, it is essential to pay attention to newborn care, that is, nutritional management's adequacy with substitute feeds (Monteiro et al., 2014). The initiation to solid feeds in lamb diets accelerates ruminal development, even though infant lambs cannot obtain fiber fermentation energy. Concentrated feeds are essential in light of the immaturity of the rumen and ease of fermentation of non-fibrous carbohydrates and offering benefits concerning the development of ruminal papillae by improving the absorption of nutrients (Chaucheyras-Durand et al., 2019; Milis et al., 2019). The feed transition that occurs in this period requires attention such that the establishment of the rumen microbiota is satisfactory, and the nutrients can be derived from the diet (Carballo et al., 2019; Cui et al., 2019).

Powdered and liquid additives offer benefits concerning administration, as they are easily added to the concentrated diet fraction (Gao et al., 2020). It is believed that the selection of feed in the diet by animals is reduced because the concentrate becomes more palatable due to the use of additives (Wall et al., 2018; Carballo et al., 2019; Gao et al., 2020). VB is a choline source different from choline chloride with commercial powder presentation, which will be explored in our study on feeding lambs during the feed transition period.

Choline participates in several body functions; it ensures the integrity of cells and tissues (Zeisel et al., 1991; Saeed et al., 2017). Choline participates in the synthesis of phospholipids, neurotransmitters, and triglycerides; also, some articles report that choline can stimulate the immune system and antioxidant responses (Zeisel and Da Costa, 2009; Repetto et al., 2010; Garcia et al., 2018). Research on choline supplementation in humans and animals has been carried out precisely because it possesses a range of physiological actions that impact health (Zeisel et al., 1991; Molano et al., 2017; Saeed et al., 2017). Some authors have quantified the concentration of choline in feeds and found that the quantities available for absorption are small (Neill et al., 1978; Zeisel et al., 2003; Baldi and Pinotti, 2006). Choline is degraded in the rumen (Sharma and Erdman, 1989; Bindel et al., 2000), and ruminally-protected choline has positive effects on milk production; the molecule minimized the negative energy balance suffered by a lactating dairy cow in the transition period when consumed in the peripartum period (Pinotti et al., 2005; Aires et al., 2016). In dairy cows, ruminally-protected choline supplementation improved metabolic profiles, decreased triglyceride and cholesterol levels, increased immunity with emphasis on stimulation of interleukin production, and decreased free radical levels that cause oxidative stress (Hartwell et al., 2000; Pinotti et al., 2003; Ardalan et al., 2010; Sun et al., 2016).

A new source of choline extracted from plants, called VB here, is rich in phosphatidylcholine. Some researchers suggest that this molecule possesses a natural resistance to ruminal degradation, i.e., bioavailability would increase for dairy cows and lambs (Rodriguez-Guerrero et al., 2018; Valencia Narváez, 2019). Although the National Research Council (2001) did not determine the nutritional requirement for choline for dairy cattle, studies suggest that growing and developing animals have greater requirements for the molecule (Al-Ali et al., 1985; Zeisel and Niculescu, 2006; Pinotti et al., 2009). We are unaware of studies evaluating VB supplementation's effects on the growth, biochemistry, and antioxidant response of lambs from dairy ewes during the feed transition. We hypothesize that, for lambs from dairy ewes, strategic supplementation with VB before and after weaning would stimulate immune responses, with antioxidant and hepatoprotective effects, consequently favoring growth. For these reasons, this study's objective was to determine the VB supplementation's growth effects, biochemistry, and antioxidant responses of lambs from dairy ewes during the feed transition period.