Feeding increasing dietary inclusions of extrudedBrassica junceacanola expeller-pressed cake on growth performance, carcass characteristics, and jowl fatty acids of growing-finishing pigs

Abstract

Zhou, X., Young, M. G., Zamora, V., Zijlstra, R. T. and Beltranena, E. 2014. Feeding increasing dietary inclusions of extruded Brassica juncea canola expeller-pressed cake on growth performance, carcass characteristics, and jowl fatty acids of growing-finishing pigs. Can. J. Anim. Sci. 94: 331–342. The energy value of canola meal is considered low because of its relatively higher fibre and depleted oil content. Brassica juncea is a novel canola species with thinner seed coat and reduced fibre, but twice the glucosinolate content of B. napus. Remaining oil in canola cake provides greater dietary energy compared with solvent-extracted meal. Extrusion prior to expeller pressing may increase fat and protein digestibility and decrease the antinutritive effects of glucosinolates. A total of 880 pigs (38 kg), housed in 40 pens by sex, were fed 0, 5, 10, 15, or 20% extruded B. juncea expeller-pressed cake (EPC) to slaughter weight (120 kg) to evaluate the effects on growth performance, dressing, carcass traits, and jowl fatty acids. Diets provided 9.6 MJ net energy (NE) and 1.0, 0.9, 0.8, 0.7, and 0.7 g standardized ileal digestible Lys:MJ NE over five growth phases (days 0–14, 15–35, 36–56, 57–74, day 75 to slaughter weight). Each 5% EPC inclusion linearly decreased (P<0.05) feed disappearance (ADFI) by 46 g and weight gain (ADG) by 8 g, but did not affect gain:feed. Each 5% EPC inclusion linearly decreased (P<0.01) carcass weight by 440 g, loin depth by 0.6 mm, and increased days on test by 0.43, but did not affect dressing, backfat thickness, lean yield, or carcass index. Each 5% EPC inclusion linearly increased (P<0.001) mono- and polyunsaturated fatty acid content and iodine value by 0.8, 1.0 and 1.4 g 100 g−1 of jowl fat, respectively. In conclusion, increasing dietary EPC inclusions decreased ADFI, ADG, carcass weight, and loin depth, and increased jowl fat unsaturation. We attributed much of the decrease in feed intake to greater 3-butenyl (9.7 µmol g−1) content in extruded B. juncea canola expeller-pressed cake, a glucosinolate more bitter than others in conventional canola.

Feeding Brassica juncea or Brassica napus canola meal at increasing dietary inclusions to growing-finishing gilts and barrows

“…The total glucosinolate level in B. napus CM fed in our trial (5.9 mol/g) was greater than the Canadian average of 3.9 mol/g (Rogiewicz et al, 2012). The glucosinolate level in B. juncea CM fed in our trial (12.3 mol/g) was greater than levels observed by Landero et al (2013;10.8 mol/g), Zhou et al (2014a;10.9 mol/g) and Le et al (2014;10.9 mol/g), but lower than levels observed by Collins et al (2011;15.9 mol/g) and Zhou et al (2013;12.5 mol/g). The main glucosinolates were progoitrin for B. napus and gluconapin for B. juncea.…”

“…The decreased carcass dressing in pigs fed B. juncea compared to B. napus CM in this trial could be due to a slight increase in the weight of the liver and thyroid in response to greater glucosinolate intake. Glucosinolate levels in B. juncea CM fed in our trial were greater than those observed in other recent experiments (Landero et al, 2013;Zhou et al, 2014a;Le et al, 2014). High glucosinolate intake increased liver weight in chickens (Woyengo et al, 2011) and liver and thyroid weight in pigs (Bourdon and Aumaître, 1990;Corino et al, 1991;Schöne et al, 1996).…”

“…However, lysine content was similar in the B. napus and B. juncea CM fed in this trial, whereas it is usually lower in B. juncea CM than B. napus CM (Bell et al, 1998;Le et al, 2012;Trindade Neto et al, 2012). The lysine content of B. juncea CM fed was higher than that observed by others (Collins et al, 2011;Landero et al, 2013;Le et al, 2014;Zhou et al, 2013Zhou et al, , 2014a.…”

“…If the SID of amino acids in CM was slightly overestimated, increasing dietary CM inclusion would decrease the SID amino acid content of the diets, thereby reducing available amino acids for lean growth. Zhou et al (2014a) also found a linear decrease in carcass weight and loin depth when feeding growing-finishing pigs extruded and expeller-pressed B. juncea cake up to 200 g/kg. However, most researchers feeding conventional CM to growing-finishing pigs did not report any effects on carcass characteristics (Mullan et al, 2000;King et al, 2001;Roth-Maier et al, 2004;Smit et al, 2014).…”

“…Moreover, for growing-finishing pigs fed diets including 150 g/kg wheat-corn DDGS and CM ranging from 0 to 240 g/kg, ADFI and ADG but not feed efficiency decreased linearly (Smit et al, 2014). Zhou et al (2014a) reported decreased ADFI and ADG as well when feeding growing-finishing pigs extruded and expeller-pressed B. juncea cake, but also did not find an effect on feed efficiency. Thus, the increased feed efficiency found in this trial with increasing dietary CM inclusions is not in agreement with the literature.…”